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 A090947 Largest prime factor of numerator of Bernoulli(2n) (or 1 if the numerator is 1). 1
 1, 1, 1, 1, 1, 5, 691, 7, 3617, 43867, 617, 593, 2294797, 657931, 362903, 1001259881, 305065927, 151628697551, 26315271553053477373, 154210205991661, 1897170067619, 1520097643918070802691, 1798482437, 67568238839737, 153289748932447906241, 47464429777438199, 4534045619429, 1120412849144121779, 19088082706840550550313, 37349583369104129, 109317926249509865753025015237911, 28765594733083851481, 87057315354522179184989699791727, 159562251828620181390358590156239282938769, 5525473366510930028227481 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,6 LINKS MATHEMATICA 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 *) CROSSREFS Cf. A000367, A079294. Sequence in context: A198597 A180315 A242193 * A176840 A000367 A176546 Adjacent sequences:  A090944 A090945 A090946 * A090948 A090949 A090950 KEYWORD nonn AUTHOR N. J. A. Sloane, Feb 28 2004 EXTENSIONS More terms from Robert G. Wilson v and Hans Havermann, Feb 28 2004 STATUS approved

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Last modified January 20 12:50 EST 2019. Contains 319330 sequences. (Running on oeis4.)