A285792 Primes equal to an octagonal number plus 1.

2, 41, 97, 281, 409, 937, 1409, 2297, 4721, 5209, 6257, 8009, 8641, 12161, 14561, 18097, 21001, 23057, 24121, 26321, 27457, 37409, 42961, 50441, 52009, 55217, 56857, 60209, 70841, 76481, 90481, 139537, 147409, 152777, 161009, 169457, 172321, 227977, 238009

Offset

1,1

Comments

Primes in A056105. - Omar E. Pol, Apr 26 2017

Links

Colin Barker, Table of n, a(n) for n = 1..1000

Mathematica

Select[PolygonalNumber[8, Range[300]]+1, PrimeQ] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Oct 22 2017 *)

Prog

(PARI) pg(m, n) = (n^2*(m-2)-n*(m-4))/2 \\ n-th m-gonal number
maxk=300; L=List(); for(k=1, maxk, if(isprime(p=pg(8, k) + 1), listput(L, p))); Vec(L)

Crossrefs

Cf. A000040, A000567, A002496, A055469, A285789, A285790, A285791.

Sequence in context: A107174 A041199 A100514 * A073468 A073186 A103335

Adjacent sequences: A285789 A285790 A285791 * A285793 A285794 A285795

Keyword

nonn

Author

Colin Barker, Apr 26 2017

Status

approved