150621(4)

Ruby


素数を順番につなぎ合わせた数について(2)

もう少し調べてみた。

# -*- coding: cp932 -*-

require 'prime'

p_ary = Prime.each(300).to_a
(0..p_ary.size - 1).each{|i|
  j = p_ary[0..i].join.to_i
  if i == 0
    p [j, 'prime']
  elsif i == 26
    p [j, '262343078386137703以下の何か']
  elsif i == 38
    p [j, '14733071537以下の何か']
  elsif i == 60
    p [j, 'prime?']
  else
    k = Math.sqrt(j).to_i
    l = 3
    while j % l > 0 && l <= k
      l += 2
    end
    if l <= k
      p [j, l]
    else
      p [j, 'prime']
    end
  end
}

出力結果

[2, "prime"]

[23, "prime"]

[235, 5]

[2357, "prime"]

[235711, 7]

[23571113, 23]

[2357111317, 11]

[235711131719, 7]

[23571113171923, 61]

[2357111317192329, 3]

[235711131719232931, 17]

[23571113171923293137, 7]

[2357111317192329313741, 25391]

[235711131719232931374143, 6899]

[23571113171923293137414347, 1597]

[2357111317192329313741434753, 3]

[235711131719232931374143475359, 17]

[23571113171923293137414347535961, 3]

[2357111317192329313741434753596167, 1019]

[235711131719232931374143475359616771, 3]

[23571113171923293137414347535961677173, 17]

[2357111317192329313741434753596167717379, 211]

[235711131719232931374143475359616771737983, 41378209]

[23571113171923293137414347535961677173798389, 3]

[2357111317192329313741434753596167717379838997, 479]

[2357111317192329313741434753596167717379838997101, 3]

[2357111317192329313741434753596167717379838997101103, "262343078386137703以下の

何か"]

[2357111317192329313741434753596167717379838997101103107, 3]

[2357111317192329313741434753596167717379838997101103107109, 107]

[2357111317192329313741434753596167717379838997101103107109113, 3]

[2357111317192329313741434753596167717379838997101103107109113127, 643]

[2357111317192329313741434753596167717379838997101103107109113127131, 3]

[2357111317192329313741434753596167717379838997101103107109113127131137, 7]

[2357111317192329313741434753596167717379838997101103107109113127131137139, 3]

[2357111317192329313741434753596167717379838997101103107109113127131137139149, 1

3]

[2357111317192329313741434753596167717379838997101103107109113127131137139149151

, 3]

[2357111317192329313741434753596167717379838997101103107109113127131137139149151

157, 107069]

[2357111317192329313741434753596167717379838997101103107109113127131137139149151

157163, 7]

[2357111317192329313741434753596167717379838997101103107109113127131137139149151

157163167, "14733071537以下の何か"]

[2357111317192329313741434753596167717379838997101103107109113127131137139149151

157163167173, 3]

[2357111317192329313741434753596167717379838997101103107109113127131137139149151

157163167173179, 61911427]

[2357111317192329313741434753596167717379838997101103107109113127131137139149151

157163167173179181, 3]

[2357111317192329313741434753596167717379838997101103107109113127131137139149151

157163167173179181191, 13]

[2357111317192329313741434753596167717379838997101103107109113127131137139149151

157163167173179181191193, 3]

[2357111317192329313741434753596167717379838997101103107109113127131137139149151

157163167173179181191193197, 31]

[2357111317192329313741434753596167717379838997101103107109113127131137139149151

157163167173179181191193197199, 3]

[2357111317192329313741434753596167717379838997101103107109113127131137139149151

157163167173179181191193197199211, 11]

[2357111317192329313741434753596167717379838997101103107109113127131137139149151

157163167173179181191193197199211223, 59]

[2357111317192329313741434753596167717379838997101103107109113127131137139149151

157163167173179181191193197199211223227, 7]

[2357111317192329313741434753596167717379838997101103107109113127131137139149151

157163167173179181191193197199211223227229, 647]

[2357111317192329313741434753596167717379838997101103107109113127131137139149151

157163167173179181191193197199211223227229233, 31]

[2357111317192329313741434753596167717379838997101103107109113127131137139149151

157163167173179181191193197199211223227229233239, 3]

[2357111317192329313741434753596167717379838997101103107109113127131137139149151

157163167173179181191193197199211223227229233239241, 13]

[2357111317192329313741434753596167717379838997101103107109113127131137139149151

157163167173179181191193197199211223227229233239241251, 3]

[2357111317192329313741434753596167717379838997101103107109113127131137139149151

157163167173179181191193197199211223227229233239241251257, 31517]

[2357111317192329313741434753596167717379838997101103107109113127131137139149151

157163167173179181191193197199211223227229233239241251257263, 43]

[2357111317192329313741434753596167717379838997101103107109113127131137139149151

157163167173179181191193197199211223227229233239241251257263269, 3]

[2357111317192329313741434753596167717379838997101103107109113127131137139149151

157163167173179181191193197199211223227229233239241251257263269271, 19]

[2357111317192329313741434753596167717379838997101103107109113127131137139149151

157163167173179181191193197199211223227229233239241251257263269271277, 127]

[2357111317192329313741434753596167717379838997101103107109113127131137139149151

157163167173179181191193197199211223227229233239241251257263269271277281, 11]

[2357111317192329313741434753596167717379838997101103107109113127131137139149151

157163167173179181191193197199211223227229233239241251257263269271277281283, "pr

ime?"]

[2357111317192329313741434753596167717379838997101103107109113127131137139149151

157163167173179181191193197199211223227229233239241251257263269271277281283293,

13]