OFFSET
0,1
LINKS
Colin Barker, Table of n, a(n) for n = 0..1000
J. Wallgren, Hierarchical sequences
Index entries for linear recurrences with constant coefficients, signature (4,-4).
FORMULA
a(n) = 12*A001787(n).
From Colin Barker, Oct 07 2015: (Start)
a(n) = 3*(2^(2+n)*(1+n)).
a(n) = 4*a(n-1)-4*a(n-2) for n>1.
G.f.: 12 / (2*x-1)^2.
(End)
PROG
(PARI) Vec(12/(2*x-1)^2 + O(x^40)) \\ Colin Barker, Oct 07 2015
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Jonas Wallgren, Feb 02 2001
STATUS
approved