The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A285792 Primes equal to an octagonal number plus 1. 4
 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 (list; graph; refs; listen; history; text; internal format)
 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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified June 13 00:57 EDT 2021. Contains 344980 sequences. (Running on oeis4.)