OFFSET
0,2
LINKS
Index entries for linear recurrences with constant coefficients, signature (12, -39, 28).
FORMULA
a(n) = (1/18) - (16/9)*4^(n-1) + (49/18)*7^(n-1). - Antonio Alberto Olivares, Feb 07 2010
a(0)=1, a(1)=12, a(n) = 11*a(n-1) - 28*a(n-2) + 1. - Vincenzo Librandi, Feb 10 2011
E.g.f.: exp(x)*(1 - 32*exp(3*x) + 49*exp(6*x))/(2!*3^2). - This is (d^2/dx^2) (exp(x)*(exp(x) - 1)^2 / (2*3^2)). See also the second column of the Sheffer triangle A282629 divided by 3^2. - Wolfdieter Lang, Apr 08 2017
MAPLE
a:=n->sum((7^(n+1-j)-4^(n+1-j))/3, j=0..n+1): seq(a(n), n=0..20); # Zerinvary Lajos, Jan 15 2007
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved