OFFSET
0,4
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
FORMULA
a(n) ~ n! / ((exp(Pi/2)-1) * (exp(-Pi/2)-1)^n). - Vaclav Kotesovec, Jan 22 2015
MAPLE
seq(coeff(series(factorial(n)*(1/cos(log(1+x))), x, n+1), x, n), n=0..20); # Muniru A Asiru, Jul 21 2018
MATHEMATICA
With[{nn = 50}, CoefficientList[Series[1/Cos[Log[1 + x]], {x, 0, nn}], x] Range[0, nn]!] (* Vincenzo Librandi, Apr 11 2014 *)
PROG
(PARI) x='x+O('x^30); Vec(serlaplace(1/cos(log(1+x)))) \\ G. C. Greubel, Jul 21 2018
(Magma) m:=30; R<x>:=PowerSeriesRing(Rationals(), m); b:=Coefficients(R!(1/Cos(Log(1+x)))); [Factorial(n-1)*b[n]: n in [1..m]]; // G. C. Greubel, Jul 21 2018
CROSSREFS
KEYWORD
sign
AUTHOR
STATUS
approved