| 1234567891011121314151617181920212223242526272829303132333435 |
- #!/usr/bin/ruby
- # Erdos construction method for Lucas-Carmichael numbers:
- # 1. Choose an integer L with many prime factors.
- # 2. Let P be the set of primes d-1, where d|L and d-1 does not divide L.
- # 3. Find a subset S of P such that prod(S) == -1 (mod L). Then prod(S) is a Lucas-Carmichael number.
- var L = 480
- var P = L.divisors.map { .dec }.grep { .is_odd && .is_prime }.grep {|p| L%p != 0 }
- for k in (3..P.len) {
- P.combinations(k, {|*S|
- if (S.prod % L == L-1) {
- say S.prod
- }
- })
- }
- __END__
- 51359
- 357599
- 6023039
- 12676799
- 16868159
- 86450399
- 1456083839
- 741722399
- 10138322879
- 3422728799
- 674628479
- 1458700319
- 39472666079
- 410636052959
- 1087044101759
|
