Largest prime <= n in any decomposition of 2n into a sum of two odd primes.
3, 3, 5, 5, 7, 5, 7, 7, 11, 11, 13, 11, 13, 13, 17, 17, 19, 17, 19, 13, 23, 19, 19, 23, 23
1 seqfan posts
Fri Dec 25 19:12:50 CET 2009 [seqfan] Re: Christmas puzzle, reformulated :)