OFFSET
0,2
COMMENTS
Binomial transform is A085351.
a(n) mod 10 = period 4:repeat 1,5,3,1 = A132400. - Paul Curtz, Nov 13 2009
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (7, -12).
FORMULA
G.f.: (1-2x)/((1-3x)(1-4x)).
E.g.f.: 2exp(4x) - exp(3x).
a(n) = 2*4^n-3^n.
From Paul Curtz, Nov 13 2009: (Start)
a(n) = 4*a(n-1) + 9*a(n-2) - 36*a(n-3);
a(n) = 4*a(n-1) + 3^(n-1), both like A005061 (note for A005061 dual formula a(n) = 3*a(n-1) + 4^(n-1) = 3*a(n-1) + A000302(n-1)).
a(n) = 3*a(n-1) + 2^(2n+1) = 3*a(n-1) + A004171(n).
MATHEMATICA
LinearRecurrence[{4, 9, -36}, {1, 5, 23}, 30] (* Harvey P. Dale, Nov 30 2011 *)
LinearRecurrence[{7, -12}, {1, 5}, 23] (* Ray Chandler, Aug 03 2015 *)
PROG
(Magma) [2*4^n-3^n: n in [0..30]]; // Vincenzo Librandi, Aug 13 2011
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Jun 24 2003
STATUS
approved