OFFSET
0,2
LINKS
Index entries for linear recurrences with constant coefficients, signature (19,-90,72).
FORMULA
a(0)=1, a(1)=19, a(n)=18*a(n-1)-72*a(n-2)+1. - Vincenzo Librandi, Feb 10 2011
a(n) = (5*12^(n+2) - 11*6^(n+2) + 6)/330. [Yahia Kahloune, Aug 13 2013]
MAPLE
a:=n->sum((12^(n-j)-6^(n-j))/6, j=0..n): seq(a(n), n=1..17); # Zerinvary Lajos, Jan 12 2007
PROG
(PARI) a(n) = (5*12^(n+2) - 11*6^(n+2) + 6)/330; \\ Joerg Arndt, Aug 13 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved