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%I #5 Aug 14 2012 04:43:21
%S 5,217,1,71,23,131,1,191,47,59,311,1,83,431,1,107,1,1,1,1,1,1,167,179,
%T 971,1,1031,1,1091,227,1,263,1,1,1,1511,1571,1,1,347,359,1811,383,
%U 1931,1,1,2111
%N Denominator of BernoulliB[10p] divided by 66, where p=Prime[n].
%C The only composite in this sequence is a(2) = 217 = 7*31. All other a(n) are equal to 1 (for n=3,7,12,15,17,18,19,20,21,22,26,28,31,33,34,35,38,39,45,46..) or prime: a(1) = 5, all other primes in a(n) belong to A068231[n]: Primes congruent to 11 (mod 12). It appears that every prime from A068231[n] except 11 shows up in a(n) just once.
%H Vincenzo Librandi, <a href="/A119657/b119657.txt">Table of n, a(n) for n = 1..500</a>
%F a(n) = Denominator[BernoulliB[10Prime[n]]]/66.
%t Table[Denominator[BernoulliB[10Prime[n]]]/66,{n,1,47}]
%Y Cf. A068231, A119456, A051230, A051229, A002445.
%K nonn
%O 1,1
%A _Alexander Adamchuk_, Jul 28 2006