A164020 Denominators of Bernoulli numbers interleaved with even numbers.

1, 2, 6, 4, 30, 6, 42, 8, 30, 10, 66, 12, 2730, 14, 6, 16, 510, 18, 798, 20, 330, 22, 138, 24, 2730, 26, 6, 28, 870, 30, 14322, 32, 510, 34, 6, 36, 1919190, 38, 6, 40, 13530, 42, 1806, 44, 690, 46, 282, 48, 46410, 50, 66, 52, 1590, 54, 798, 56, 870, 58, 354, 60, 56786730

Offset

0,2

Links

G. C. Greubel, Table of n, a(n) for n = 0..1000

Eric Weisstein's World of Mathematics, Bernoulli Number

Formula

a(2*n) = A002445(n).

a(2*n+1) = 2*(n+1).

a(n) divides A057643(n). Franklin T. Adams-Watters, Aug 03 2012

Mathematica

a[n_]:=If[OddQ[n], n+1, BernoulliB[n] // Denominator]; Table[a[n], {n, 0, 60}](* Jean-François Alcover, Dec 29 2012 *)
With[{nn=60}, Riffle[Denominator[BernoulliB[Range[0, nn, 2]]], Range[2, nn, 2]]] (* Harvey P. Dale, Jul 18 2015 *)

Prog

(Magma) [IsEven(n) select Denominator(Bernoulli(n)) else n+1: n in [0..100]]; // Vincenzo Librandi, Sep 08 2017

Crossrefs

Cf. A027642, A141056, A160014.

Sequence in context: A226532 A335049 A006233 * A326579 A057643 A073039

Adjacent sequences: A164017 A164018 A164019 * A164021 A164022 A164023

Keyword

nonn

Author

Paul Curtz, Aug 08 2009

Extensions

Extended by R. J. Mathar, Sep 23 2009

Status

approved