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%I A090947 #14 Feb 09 2020 08:39:44
%S A090947 1,1,1,1,1,5,691,7,3617,43867,617,593,2294797,657931,362903,
%T A090947 1001259881,305065927,151628697551,26315271553053477373,
%U A090947 154210205991661,1897170067619,1520097643918070802691,1798482437,67568238839737,153289748932447906241,47464429777438199,4534045619429,1120412849144121779,19088082706840550550313,37349583369104129,109317926249509865753025015237911,28765594733083851481,87057315354522179184989699791727,159562251828620181390358590156239282938769,5525473366510930028227481
%N A090947 Largest prime factor of numerator of Bernoulli(2n) (or 1 if the numerator is 1).
%H A090947 Amiram Eldar, <a href="/A090947/b090947.txt">Table of n, a(n) for n = 0..103</a>
%F A090947 a(n) = A006530(abs(A000367(n))). - _Amiram Eldar_, Feb 09 2020
%t A090947 PrimeFactors[ n_] := Flatten[ Table[ #[[1]], {1} ] & /@ FactorInteger[ n ]]; A090947[n_] := PrimeFactors[ Numerator[ BernoulliB[2n]]][[ -1]]; Table[ A090947[n], {n, 5, 24}] (* _Robert G. Wilson v_, Feb 28 2004 *)
%Y A090947 Cf. A000367, A006530, A079294.
%K A090947 nonn
%O A090947 0,6
%A A090947 _N. J. A. Sloane_, Feb 28 2004
%E A090947 More terms from _Robert G. Wilson v_ and _Hans Havermann_, Feb 28 2004

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