OFFSET
1,2
LINKS
Seiichi Manyama, Table of n, a(n) for n = 1..65
FORMULA
a(n) = 3^(n-1)*a(n-1) + a(n-2).
EXAMPLE
G.f. = x + 4*x^2 + 37*x^3 + 1003*x^4 + 81280*x^5 + 19752043*x^6 + ...
a(3) = 37, the numerator of 1 + 1/(3 + 1/9) = 37/28.
MATHEMATICA
f[n_] := Numerator[ FromContinuedFraction[ Reverse[3^Range[0, n -1]] ]]; Array[f, 14] (* Robert G. Wilson v, Dec 30 2016 *)
CROSSREFS
KEYWORD
nonn,frac
AUTHOR
Seiichi Manyama, Dec 29 2016
STATUS
approved