A185938 First of a run of 3 or more consecutive primes which are congruent to 2 (mod 3).

47, 167, 251, 257, 503, 557, 587, 647, 941, 971, 1097, 1181, 1217, 1361, 1493, 1499, 1889, 1901, 1907, 2063, 2393, 2399, 2411, 2441, 2897, 2957, 3191, 3797, 4007, 4073, 4373, 4391, 4397, 4451, 4457, 4673, 4679, 4691, 4871, 5081, 5237, 5261, 5297, 5351, 5381, 5387, 5801, 6257, 6311, 6317, 6857, 6911, 6971, 7001, 7079

Offset: 1

Author

M. F. Hasler, Feb 06 2011

Keywords

• nonn

Comments

The subsequence of terms A185935(k) such that nextprime(A185935(k))=A185935(k+1). If nextprime(a(n))=a(n+1), then a(n) is in A185941.

Links

• Paolo Xausa, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A185935, A185936, A185941.

Programs

Mathematica

Select[Partition[Prime[Range[1500]], 3, 1], Mod[#, 3] == {2, 2, 2} &][[All, 1]] (* Paolo Xausa, Mar 07 2025 *)

PARI

my(s=Mod([2,2,2],3), o=vector(#s), i=0); forprime( p=1,1e4, o[i++%3+1]=p; o-s || print1( o[(i+1)%3+1], ", "))