A283020 For p = prime(n), number of iterations of the function f(x) = 2*x^3-1 that leave p prime.

0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0

Offset

1

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Prog

(PARI) a(n) = my(p=prime(n), i=0); while(1, if(!ispseudoprime(2*p^3-1), return(i), p=2*p^3-1; i++))

Crossrefs

Cf. A177104, A282989.

Sequence in context: A130638 A030217 A030215 * A098108 A363712 A030214

Adjacent sequences: A283017 A283018 A283019 * A283021 A283022 A283023

Keyword

nonn

Author

Felix Fröhlich, Feb 26 2017

Status

approved