OFFSET
1,2
LINKS
Colin Barker, Table of n, a(n) for n = 1..600
Index entries for linear recurrences with constant coefficients, signature (50,-553,1800,-1296).
FORMULA
a(n) = (1/12)*(36^n - 2*9^n - 3*4^n+6).
From Colin Barker, May 30 2020: (Start)
G.f.: x*(1 - 6*x)*(1 + 47*x + 36*x^2) / ((1 - x)*(1 - 4*x)*(1 - 9*x)*(1 - 36*x)).
a(n) = 50*a(n-1) - 553*a(n-2) + 1800*a(n-3) - 1296*a(n-4) for n>4.
(End)
PROG
(PARI) a(n)=(1/12)*36^n-(1/6)*9^n-(1/4)*4^n+1/2
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Benoit Cloitre, Jun 18 2004
STATUS
approved