OFFSET
0,2
COMMENTS
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..500
FORMULA
a(n) = denominator(r(n)), with r(n) = [x^n]( 1 - 3*x/8 + Sum_{k >= 0}((B(2*k)/((2*k+3)*(2*k)!))*x^(2*k) ), where B(2*k) = A000367(k)/A002445(k) (Bernoulli numbers).
a(n) = denominator( 3*Bernoulli(n)/((n+3)*n!) ), n >= 0. - G. C. Greubel, May 01 2023
MATHEMATICA
max = 26; Denominator[CoefficientList[Integrate[Normal[Series[(3*(t^3/(Exp[t] -1)))/x^3, {t, 0, max}]], {t, 0, x}], x]] (* Jean-François Alcover, Oct 04 2011 *)
Table[Denominator[3*BernoulliB[n]/((n+3)*n!)], {n, 0, 50}] (* G. C. Greubel, May 01 2023 *)
PROG
(Magma) [Denominator(3*Bernoulli(n)/((n+3)*Factorial(n))): n in [0..50]]; // G. C. Greubel, May 01 2023
(SageMath)
def A120081(n): return denominator(3*bernoulli(n)/((n+3)*factorial(n)))
[A120081(n) for n in range(51)] # G. C. Greubel, May 01 2023
CROSSREFS
KEYWORD
nonn,easy,frac
AUTHOR
Wolfdieter Lang, Jul 20 2006
STATUS
approved