A064713 Numbers k such that prime(k)^2 - k is prime.

1, 2, 6, 8, 20, 30, 42, 48, 50, 60, 68, 96, 110, 122, 132, 168, 204, 222, 234, 284, 306, 332, 336, 366, 378, 392, 398, 402, 420, 440, 474, 488, 492, 506, 516, 518, 530, 572, 594, 600, 650, 672, 680, 740, 756, 762, 770, 810, 870, 884, 888, 902, 920, 930, 938

Offset

1,2

Links

Harry J. Smith, Table of n, a(n) for n = 1..1000

Example

6 is in the sequence because prime(6)^2 - 6 = 169 - 6 = 163 is a prime.

Maple

A064713:=n->`if`(isprime(ithprime(n)^2-n), n, NULL): seq(A064713(n), n=1..2*10^3); # Wesley Ivan Hurt, Jan 21 2017

Mathematica

Select[Range[1000], PrimeQ[Prime[#]^2-#]&] (* Harvey P. Dale, May 17 2013 *)

Prog

(PARI) { n=0; for (m=1, 10^9, if (isprime(prime(m)^2 - m), write("b064713.txt", n++, " ", m); if (n==1000, break)) ) } \\ Harry J. Smith, Sep 23 2009

Crossrefs

Cf. A064361.

Sequence in context: A371238 A143481 A093968 * A162213 A100358 A134136

Adjacent sequences: A064710 A064711 A064712 * A064714 A064715 A064716

Keyword

easy,nonn

Author

Robert G. Wilson v, Oct 13 2001

Status

approved