%I #12 Aug 17 2020 01:58:31
%S 5,9,15,50943795,40874929095,616517522595975,93487500801880185,
%T 64606701602327559675
%N a(n) = smallest m such that m+2^j and m-2^j are prime for all 0 < j <= n.
%C Is this sequence infinite?
%H Felice Russo, <a href="http://www.primepuzzles.net/puzzles/puzz_167.htm">Prime puzzle 167</a>.
%H Marek Wolf, <a href="https://pdfs.semanticscholar.org/78a1/7349819304863ae061df88dbcb26b4908f03.pdf">Conjectures on the gaps between consecutive primes</a>
%e 9-4, 9-2, 9+2, 9+4 are prime, but not 5+4 = 7+2, therefore a(2) = 9.
%Y Prime quadruples: A014561, sextets: A061671, octets: A066082.
%K hard,nonn
%O 1,1
%A _Frank Ellermann_, Dec 03 2001
%E a(5) and a(6) from _Don Reble_, Dec 07 2001
%E a(7) from Jim Fougeron (Feb 07) confirmed by Phil Carmody, who also found a(8) (Feb 14 2002).