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

Author

Vladimir Joseph Stephan Orlovsky, Apr 03 2009

Keywords

• nonn
• easy

Examples

			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.
		

Links

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

Crossrefs

Cf. A055469, A055472, A159047, A159048

Programs

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 *)

PARI

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

Extensions

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