A145477 - OEIS

A145477

Primes p such that (23 + p)/2 is prime.

3, 11, 23, 59, 71, 83, 179, 191, 239, 251, 311, 359, 431, 443, 479, 491, 503, 563, 599, 683, 743, 839, 863, 911, 983, 1019, 1091, 1103, 1151, 1163, 1259, 1283, 1499, 1523, 1571, 1619, 1871, 1931, 2003, 2039, 2099, 2339, 2351, 2411, 2423, 2531, 2543, 2579

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

OFFSET

1,1

COMMENTS

All these primes are congruent to 3 mod 4 and (with the exception of the first term) to 11 mod 12.

LINKS

Ivan Neretin, Table of n, a(n) for n = 1..10000

MATHEMATICA

aa = {}; k = 23; Do[If[PrimeQ[(k + Prime[n])/2], AppendTo[aa, Prime[n]]], {n, 1, 500}]; aa

Select[Prime[Range[400]], PrimeQ[(23+#)/2]&] (* Harvey P. Dale, Jan 26 2024 *)

PROG

(PARI) list(n)=my(t=1, p, i=1); while(i<n, p=prime(i); i=i+1; if(p>2&&prime((23+p)/2), print1(p, ", "))) \\ Anders Hellström, Jan 23 2017