A114648 - OEIS

%I #20 Aug 17 2015 16:38:39

%S 0,1,10,87,834,7992,77696,758582,7436825,73129588,720726912

%N Number of occurrences of 6 as a denominator in Bernoulli(k) for 0<=k<=10^n.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/BernoulliNumber.html">Bernoulli Number</a>

%t DenominatorBernoulliBQ[n_Integer, denom_Integer] := If[EvenQ[n], Times @@ Select[Divisors[n] + 1, PrimeQ] == denom, 1 + KroneckerDelta[n, 1] == denom]; A114648[n_] := A114648[n] = Length[Select[Range[10^n], DenominatorBernoulliBQ[#, 6] &]] (* _Enrique Pérez Herrero_, Aug 01 2010 *)

%Y Cf. A002445, A114649.

%Y Cf. A051222, A045979. - _Enrique Pérez Herrero_, Aug 16 2010

%K nonn,hard

%O 0,3

%A _Eric W. Weisstein_, Dec 21 2005

%E More terms added by _Enrique Pérez Herrero_, Aug 01 2010

%E More terms from _Enrique Pérez Herrero_, Aug 16 2010

%E a(10) from _Arkadiusz Wesolowski_, Dec 02 2012