A195855 a(n) = T(9,n), array T given by A048505.

1, 101, 322, 808, 1872, 4192, 9232, 20144, 43696, 94384, 203184, 436144, 933808, 1994672, 4251568, 9043888, 19201968, 40697776, 86114224, 181927856, 383778736, 808452016, 1700790192, 3573546928, 7499415472, 15720251312, 32916897712, 68853694384, 143881404336

Offset

0,2

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+37*n+324)*2^(n-2) - 80.

From Colin Barker, Feb 25 2015: (Start)

a(n) = 7*a(n-1) - 18*a(n-2) + 20*a(n-3) - 8*a(n-4).

G.f.: (352*x^3-367*x^2+94*x+1)/((x-1)*(2*x-1)^3). (End)

E.g.f.: exp(x)*(exp(x)*(81 + 19*x + x^2) - 80). - Elmo R. Oliveira, Oct 30 2025

Mathematica

LinearRecurrence[{7, -18, 20, -8}, {1, 101, 322, 808}, 30] (* Harvey P. Dale, Jan 08 2023 *)

Prog

(Magma) [(n^2+37*n+324)*2^(n-2)-80: n in [0..30]];
(PARI) a(n)=(n^2+37*n+324)<<(n-2)-80 \\ Charles R Greathouse IV, Dec 27 2011
(PARI) Vec((352*x^3-367*x^2+94*x+1)/((x-1)*(2*x-1)^3) + O(x^100)) \\ Colin Barker, Feb 25 2015

Crossrefs

Cf. A048505, A048506, A048507, A048508, A048509, A048510, A048511, A048512, A048513, A048514, A048515.

Sequence in context: A134971 A082770 A161907 * A142769 A282406 A142264

Adjacent sequences: A195852 A195853 A195854 * A195856 A195857 A195858

Keyword

nonn,easy

Author

Vincenzo Librandi, Sep 25 2011

Status

approved