A281332 Greatest prime factor of |A001067(n)|, or 1 if |A001067(n)| = 1.

1, 1, 1, 1, 1, 691, 1, 3617, 43867, 617, 593, 2294797, 657931, 362903, 1001259881, 305065927, 151628697551, 26315271553053477373, 154210205991661, 1897170067619, 1520097643918070802691, 1798482437, 67568238839737, 153289748932447906241, 47464429777438199

Offset

1,6

Links

Table of n, a(n) for n=1..25.

Formula

a(n) = A006530(|A001067(n)|).

If n = A112548(m)/2, a(n) = |A001067(n)|.

Example

|A001067(10)| = 174611 = 283*617. So a(10) = 617.
|A001067(16)| = 7709321041217 = 37*683*305065927. So a(16) = 305065927.

Mathematica

Table[FactorInteger[Abs@ Numerator[BernoulliB[2 n]/(2 n)]][[-1, 1]], {n, 25}] (* Michael De Vlieger, Jan 21 2017 *)

Prog

(PARI) a(n) = if(abs(numerator(bernfrac(2*n) / (2*n))) == 1, 1, vecmax(factor(abs(numerator(bernfrac(2*n) / (2*n))))[, 1]));
for(n=1, 25, print1(a(n), ", ")) \\ Indranil Ghosh, Mar 11 2017

Crossrefs

Cf. A000928, A001067, A006530, A033563, A112548, A281331.

Sequence in context: A249699 A141588 A281331 * A046968 A255505 A001067

Adjacent sequences: A281329 A281330 A281331 * A281333 A281334 A281335

Keyword

nonn

Author

Seiichi Manyama, Jan 20 2017

Extensions

a(20)-a(25) from Michael De Vlieger, Jan 21 2017

Status

approved