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- #!/usr/bin/ruby
- # Largest prime factor of (p^p-1)/(p-1) where p = prime(n).
- # https://oeis.org/A214812
- # First few terms:
- # 3, 13, 71, 4733, 1806113, 1803647, 2699538733, 109912203092239643840221, 1920647391913, 549334763, 568972471024107865287021434301977158534824481, 41903425553544839998158239, 5926187589691497537793497756719, 19825223972382274003506149120708429799166030881820329892377241, 194707033016099228267068299180244011637
- include("../../../factordb/auto.sf")
- func a(n) {
- var p = prime(n)
- (p**p - 1) / (p-1)
- }
- var bfile = File("bfile.txt").open_w.autoflush(true)
- for n in (1..10000) {
- var k = a(n)
- var row = "#{n} #{gpf(k)||1}"
- say row
- bfile.say(row)
- }
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