A092519 Smallest prime a(n) such that a(n)+6n, a(n)+12n and a(n)+18n are also primes.

5, 5, 5, 59, 7, 31, 5, 5, 5, 11, 31, 7, 23, 5, 11, 5, 7, 23, 79, 29, 5, 5, 73, 29, 7, 41, 107, 43, 19, 59, 11, 37, 13, 79, 13, 11, 17, 43, 359, 23, 31, 5, 53, 19, 47, 181, 137, 23, 59, 7, 491, 127, 283, 179, 23, 11, 7, 5, 89, 7, 461, 7, 53, 139, 31, 5, 7, 13

Offset: 1

Author

Ray G. Opao, Apr 06 2004

Keywords

• nonn

Examples

			a(5) = 7: 7+6*5 = 7+30 = 37, 7+12*5 = 7+60 = 67, and 7+18*5 = 7+90 = 97 are all prime.
		

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..2000

Crossrefs

a(1) starts sequence A023271.

Programs

Magma

prs := [NthPrime(i) : i in [1..200]]; result := []; for n in [1..100] do  for p in prs do if forall{k : k in [1..3] | IsPrime(p + 6*n*k)} then  Append(~result, p); break; end if; end for; end for; result; // Vincenzo Librandi, Jul 26 2025

Mathematica

Module[{nn=100,prs},prs=Prime[Range[nn]];Table[SelectFirst[prs, AllTrue[ #+6*Range[3]*n,PrimeQ]&],{n,nn/2}]] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Dec 22 2018 *)