OFFSET
1,2
LINKS
Index entries for linear recurrences with constant coefficients, signature (12,-47,72,-36)
FORMULA
a(n) = 6^n - 3*2^n - 3^n + 3.
G.f.: 6*x^2*(3 - 8*x) / (1 - 12*x + 47*x^2 - 72*x^3 + 36*x^4). [Corrected by Georg Fischer, May 15 2019]
MATHEMATICA
LinearRecurrence[{12, -47, 72, -36}, {0, 18, 168, 1170, 7440}, 23] (* Georg Fischer, May 15 2019 *)
PROG
(PARI) a(n) = 6^n - 3*2^n - 3^n + 3; \\ Michel Marcus, Oct 31 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Sharon Sela (sharonsela(AT)hotmail.com), Jun 02 2002
EXTENSIONS
More terms from Michel Marcus, Oct 31 2017
STATUS
approved