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- #!/usr/bin/ruby
- # Smallest base-n strong Fermat pseudoprime with n distinct prime factors.
- # See also:
- # https://oeis.org/A271874
- func a(n) {
- return nil if (n < 2)
- var x = 1
- var y = 2*x
- loop {
- #say "Sieving range: #{[x,y]}"
- var arr = n.strong_fermat_psp(n,x,y)
- if (arr.len >= 1) {
- return arr[0]
- }
- x = y+1
- y = 2*x
- }
- }
- for n in (2..100) {
- say "a(#{n}) = #{a(n)}"
- }
- __END__
- a(2) = 2047
- a(3) = 8911
- a(4) = 129921
- a(5) = 381347461
- a(6) = 333515107081
- a(7) = 37388680793101
- a(8) = 713808066913201
- a(9) = 665242007427361
- a(10) = 179042026797485691841
- a(11) = 8915864307267517099501
- a(12) = 331537694571170093744101
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