A145838 Primes in A005891 = Centered pentagonal numbers: (5n^2 + 5n + 2)/2.

31, 181, 331, 601, 1051, 1381, 3331, 4951, 5641, 5881, 9151, 11731, 12781, 14251, 17431, 17851, 19141, 21391, 31081, 33931, 41281, 43891, 51481, 52201, 61231, 63601, 67651, 70141, 70981, 84181, 92641, 100501, 104551, 107641, 116101, 126001

Offset

1,1

Links

Table of n, a(n) for n=1..36.

Eric Weisstein's World of Mathematics, Centerd Pentagonal Number

Maple

A005891 := proc(n) (5*n*(n+1)+2)/2 ; end: for n from 1 to 1000 do c := A005891(n) ; if isprime(c) then printf("%d, ", c) ; fi; od: # R. J. Mathar, Nov 02 2008

Crossrefs

Cf. A005891 = Centered pentagonal numbers: (5n^2 + 5n + 2)/2.

Sequence in context: A331759 A325080 A139496 * A243522 A227523 A055788

Adjacent sequences: A145835 A145836 A145837 * A145839 A145840 A145841

Keyword

nonn

Author

Alexander Adamchuk, Oct 21 2008

Extensions

More terms from R. J. Mathar, Nov 02 2008

Status

approved