A066081 a(n) = smallest m such that m+2^j and m-2^j are prime for all 0 < j <= n.

5, 9, 15, 50943795, 40874929095, 616517522595975, 93487500801880185, 64606701602327559675

Offset: 1

Author

Frank Ellermann, Dec 03 2001

Keywords

• hard
• nonn

Comments

Is this sequence infinite?

Examples

			9-4, 9-2, 9+2, 9+4 are prime, but not 5+4 = 7+2, therefore a(2) = 9.
		

Links

• Felice Russo, Prime puzzle 167.
• Marek Wolf, Conjectures on the gaps between consecutive primes

Crossrefs

Prime quadruples: A014561, sextets: A061671, octets: A066082.

Extensions

a(5) and a(6) from Don Reble, Dec 07 2001

a(7) from Jim Fougeron (Feb 07) confirmed by Phil Carmody, who also found a(8) (Feb 14 2002).