OFFSET
0,3
COMMENTS
LINKS
Bruno Berselli, Table of n, a(n) for n = 0..1000
G. Xiao, Contfrac.
Index entries for linear recurrences with constant coefficients, signature (0,2,0,-1).
FORMULA
MATHEMATICA
ContinuedFraction[3 Tanh[1/3], 158]
CoefficientList[Series[x (1 + 27 x + 3 x^2 + 9 x^3) / ((1 - x)^2 (1 + x)^2), {x, 0, 60}], x] (* Vincenzo Librandi, Jun 14 2013 *)
PROG
(PARI) \p232;
contfrac(3*tanh(1/3))
(Magma) I:=[0, 1, 27, 5, 63]; [n le 5 select I[n] else 2*Self(n-2)-Self(n-4): n in [1..58]];
(Maxima) makelist(coeff(taylor(x*(1+27*x+3*x^2+9*x^3)/((1-x)^2*(1+x)^2), x, 0, n), x, n), n, 0, 57);
CROSSREFS
KEYWORD
nonn,cofr,easy
AUTHOR
Bruno Berselli, Jan 23 2012
STATUS
approved