OFFSET
0,12
COMMENTS
Ratios of two similar sequences.
This sequence is related to the sequences of the numerators and denominators of the Taylor series for tan(x), i.e., A002430 and A036279, and the similar sequences A160469 and A156769. - Johannes W. Meijer, May 24 2009
LINKS
Michael De Vlieger, Table of n, a(n) for n = 0..5000
FORMULA
For n>=0, a(n)=c(n+1) where c(n)=numerator((4^n-1)*B(2*n)/n)/numerator((4^n-1)*B(2*n)/(2*n)!), B(k) denotes the k-th Bernoulli number. - C. Ronaldo (aga_new_ac(AT)hotmail.com), Dec 19 2004
MAPLE
seq(numer(2*bernoulli(2*n)*(4^n-1)/(2*n))/numer((4^n-1)*bernoulli(2*n)/(2*n)!), n=1..100); # C. Ronaldo
MATHEMATICA
Table[Numerator[2*BernoulliB[2*n]*(4^n -1)/(2*n)]/Numerator[SeriesCoefficient[Series[1/(1+Cosh[x]), {x, 0, 2n}], 2n-2]], {n, 1, 128}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Wouter Meeussen, Dec 07 2003
STATUS
approved