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%I #21 Jan 28 2017 19:33:34
%S 1,25,35,49,65,77,85,91,95,115,119,121,125,133,143,145,155,161,169,
%T 175,185,187,203,205,209,215,217,221,235,245,247,259,265,287,289,295,
%U 299,301,305,319,323,325,329,335,341,343,355,361,365,371,377,391,395,403
%N Odd nonprimes c which divide Bernoulli(2*c).
%C a(n) == +- 1 (mod 6).
%C First differences: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24. - _Robert G. Wilson v_, Jan 26 2017
%H Robert G. Wilson v, <a href="/A060976/b060976.txt">Table of n, a(n) for n = 1..5373</a>
%t Do[ If[ Mod[ Numerator[ BernoulliB[ 2*n ] ], 2n ] == 0 && ! PrimeQ[ n ], Print[ n ] ], {n, 1, 250, 2} ]
%o (PARI) select(n->n%2&!isprime(n)&numerator(bernfrac(2*n))%n==0,vector(1000,i,i)) \\ _Charles R Greathouse IV_, May 26 2011
%K nonn
%O 1,2
%A _Robert G. Wilson v_, May 09 2001
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