Numbers n such that at least one of n and n+2 is composite while for every b relatively prime to n*(n+2), b^(n-1)==1 mod n and b^(n+1)==1 mod n+2.
561, 1103, 2465, 2819, 6599, 29339, 41039, 52631, 62743, 172079, 188459, 278543
2 seqfan posts
Wed Oct 12 23:28:33 CEST 2011 [seqfan] Re: " Little Fermat theorem" for twin primes