A159049 Primes of the form (5+ a triangular number A000217).

5, 11, 41, 71, 83, 281, 383, 1181, 1601, 2351, 2633, 3491, 3833, 4283, 5783, 6221, 6791, 8783, 10301, 10883, 11633, 12251, 14033, 15581, 18341, 26111, 26801, 30881, 31883, 34721, 38231, 41333, 41621, 42491, 43961, 46061, 47591, 53633, 60383

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Example

11 is in the list because it is A000217(3)+5 and a prime. 41=36+5= A000217(8)+5 is a prime. 71=66+5=A000217(11)+5 is a prime.

Mathematica

s=0; lst={}; Do[s+=n; p=s+5; If[PrimeQ[p], AppendTo[lst, p]], {n, 0, 7!}]; lst
Select[Accumulate[Range[0, 500]]+5, PrimeQ] (* Harvey P. Dale, Jul 08 2017 *)

Prog

(PARI) for(n=1, 500, if(isprime(k=n*(n+1)/2 + 5), print1(k, ", "))) \\ G. C. Greubel, Jul 13 2017

Crossrefs

Cf. A055469, A055472, A159047, A159048

Sequence in context: A089441 A046121 A023271 * A343712 A047976 A006382

Adjacent sequences: A159046 A159047 A159048 * A159050 A159051 A159052

Keyword

nonn,easy

Author

Vladimir Joseph Stephan Orlovsky, Apr 03 2009

Extensions

Definition rephrased, R. J. Mathar, Apr 05 2009

Status

approved