OFFSET
0,2
COMMENTS
n-th difference of a(n), a(n-1), ..., a(0) is (25, 36, 49, 64, 81...).
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..2000
Index entries for linear recurrences with constant coefficients, signature (7,-18,20,-8).
FORMULA
a(n) = (n^2+17*n+64) * 2^(n-2) - 15. - Ralf Stephan, Feb 05 2004
a(n) = 7*a(n-1)-18*a(n-2)+20*a(n-3)-8*a(n-4). - Colin Barker, Mar 04 2015
G.f.: (72*x^3-77*x^2+19*x+1) / ((x-1)*(2*x-1)^3). - Colin Barker, Mar 04 2015
MATHEMATICA
LinearRecurrence[{7, -18, 20, -8}, {1, 26, 87, 233}, 30] (* Harvey P. Dale, Jul 08 2023 *)
PROG
(Magma) [(n^2+17*n+64) * 2^(n-2) - 15: n in [0..30]]; // Vincenzo Librandi, Sep 26 2011
(PARI) Vec((72*x^3-77*x^2+19*x+1)/((x-1)*(2*x-1)^3) + O(x^100)) \\ Colin Barker, Mar 04 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved