A237495 Primes which start a Cunningham chain of length 5 where every prime in the chain is the smaller of a pair of twin primes.

41887255409, 364223689829, 376655795669, 790031896499, 1558600513469, 2180283962009, 3266149150109, 4424063189699, 4655123392919, 6924093600269, 7706450161409, 9792446379869, 14825914106849, 15049625144399, 15612571518389, 18228407987789, 20440411077239

Offset: 1

Author

Abhiram R Devesh, Feb 08 2014

Keywords

• nonn

Comments

This is subset of the sequence A236443. Of the first 10000 terms in the sequence A236443 only 48 have length 5.

a(n) generates a Cunningham chain of length 5 and a_n(i) + 2 is also prime for i = 1,2,3,4 and 5.

This sequence is infinite under Dickson's conjecture.

Examples

			a(1) = 41887255409, with associated Cunningham chain of length 5: 41887255409, 83774510819, 167549021639, 335098043279, 670196086559, each of which is the smaller of a pair of twin primes.
		

Links

• David Radcliffe, Table of n, a(n) for n = 1..284 (terms 1..48 from Abhiram R Devesh).
• Chris Caldwell, Cunningham Chain

Crossrefs

Cf. A178421, A005602, A236443 is a superset of this sequence.

Extensions

a(11)-a(17) from David Radcliffe, Aug 09 2025