A163418 - OEIS

A163418

Primes of the form ((p-1)/2)^2+((p+1)/2), where p is prime.

3, 7, 13, 31, 43, 73, 211, 241, 421, 463, 1123, 1723, 2551, 2971, 4831, 5701, 6163, 8011, 8191, 9901, 11131, 12433, 14281, 17293, 19183, 20023, 23563, 24181, 28393, 30103, 31153, 35911, 37831, 43891, 46441, 53593, 60271, 77563, 83233, 86143

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Subsequence of A002383. - Charles R Greathouse IV, Aug 11 2009

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..1500

EXAMPLE

((3-1)/2)^2+((3+1)/2)=1+2=3;

((5-1)/2)^2+((5+1)/2)=4+3=7;

((7-1)/2)^2+((7+1)/2)=9+4=13,..

MATHEMATICA

f[n_]:=((p-1)/2)^2+((p+1)/2); lst={}; Do[p=Prime[n]; If[PrimeQ[f[p]], AppendTo[lst, f[p]]], {n, 6!}]; lst

Select[((#-1)/2)^2+((#+1)/2)&/@Prime[Range[200]], PrimeQ] (* Harvey P. Dale, Aug 06 2012 *)

PROG

(PARI) forprime(p=3, 10^3, if(isprime(q=((p-1)/2)^2+(p+1)/2), print1(q, ", "))) \\ Derek Orr, Apr 30 2015

CROSSREFS

Cf. A162652.

Sequence in context: A079018 A342150 A002383 * A309738 A161218 A351318

Adjacent sequences: A163415 A163416 A163417 * A163419 A163420 A163421

KEYWORD

nonn,easy

AUTHOR

Vladimir Joseph Stephan Orlovsky, Jul 27 2009

STATUS

approved