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A281331
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Smallest prime factor of |A001067(n)|, or 1 if |A001067(n)| = 1.
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1
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1, 1, 1, 1, 1, 691, 1, 3617, 43867, 283, 131, 103, 657931, 9349, 1721, 37, 151628697551, 26315271553053477373, 154210205991661, 137616929, 1520097643918070802691, 59, 383799511, 653, 417202699, 577, 39409, 113161, 67, 2003, 157, 1226592271, 839, 37, 688531, 3112655297839
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OFFSET
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1,6
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LINKS
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FORMULA
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a(18*m-2) = 37 for m > 0.
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EXAMPLE
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|A001067(10)| = 174611 = 283*617. So a(10) = 283.
|A001067(16)| = 7709321041217 = 37*683*305065927. So a(16) = 37.
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MATHEMATICA
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a[n_] := FactorInteger[Abs[Numerator[BernoulliB[2*n] / (2*n)]]][[1, 1]]; Table[a[n], {n, 1, 36}] (* Indranil Ghosh, Mar 12 2017 *)
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PROG
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(PARI) a(n) = my(num = abs(numerator(bernfrac(2*n)/(2*n)))); if (num==1, 1, factor(num)[1, 1]); \\ Michel Marcus, Jan 21 2017
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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