OFFSET
0,3
COMMENTS
These are also the denominators of a sequence generated by inverse binomial transform of a modified Bernoulli sequence described in (with numerators in) A176328.
LINKS
Antti Karttunen, Table of n, a(n) for n = 0..4096
MAPLE
read("transforms") ; evb := [1, 0, seq(bernoulli(n), n=2..50)] ; BINOMIALi(evb) ; apply(denom, %) ; # R. J. Mathar, Dec 01 2010
seq(denom((bernoulli(i, 1)+bernoulli(i, 2))/2), i=0..50); # Peter Luschny, Jun 17 2012
MATHEMATICA
a[n_] := If[OddQ[n], 2, BernoulliB[n] // Denominator]; a[1] = 1; Table[a[n], {n, 0, 50}] (* Jean-François Alcover, Dec 29 2012 *)
Join[{1, 1}, BernoulliB[Range[2, 80]]/.(0->1/2)//Denominator] (* Harvey P. Dale, Dec 31 2018 *)
PROG
(PARI) A176591(n) = { my(p=1); if(n>1, fordiv(n, d, my(r=d+1); if(isprime(r), p = p*r))); return(p); }; \\ Antti Karttunen, Dec 20 2018, after code in A141056
CROSSREFS
KEYWORD
nonn,frac
AUTHOR
Paul Curtz, Apr 21 2010
EXTENSIONS
More terms from Antti Karttunen, Dec 20 2018
STATUS
approved