OFFSET
0,2
COMMENTS
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (18,-108,216).
FORMULA
a(n) = 6^n*(n^2 + 23*n + 72)/72.
G.f.: (1-5*x)^2/(1-6*x)^3.
E.g.f.: (2 + 4*x + x^2)*exp(6*x)/2. - G. C. Greubel, Oct 17 2018
MAPLE
seq(coeff(series((1-5*x)^2/(1-6*x)^3, x, n+1), x, n), n = 0 .. 20); # Muniru A Asiru, Oct 18 2018
MATHEMATICA
Table[6^n*(n^2+23*n+72)/72, {n, 0, 50}] (* or *) LinearRecurrence[{18, -108, 216}, {1, 8, 61}, 50] (* G. C. Greubel, Oct 17 2018 *)
PROG
(PARI) vector(50, n, n--; 6^n*(n^2 +23*n +72)/72) \\ G. C. Greubel, Oct 17 2018
(Magma) [6^n*(n^2 +23*n +72)/72: n in [0..50]]; // G. C. Greubel, Oct 17 2018
(GAP) List([1..20], n->6^(n-1)*(n^2+21*n+50))/72; # Muniru A Asiru, Oct 18 2018
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Mar 30 2003
STATUS
approved