A128048 (n^3+n)*8^n.

16, 640, 15360, 278528, 4259840, 58195968, 734003200, 8724152320, 99052683264, 1084479242240, 11527692222464, 119571889520640, 1214960348692480, 12129812277624832, 119275021381140480, 1157425104234217472

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (32,-384,2048,-4096).

Formula

G.f.: 16*x*(1+8*x+64*x^2)/(1-8*x)^4. - Vincenzo Librandi, Feb 22 2013

a(n) = 32*a(n-1) -384*a(n-2) +2048*a(n-3) -4096*a(n-4). - Vincenzo Librandi, Feb 23 2013

Mathematica

Table[(n^3 + n) 8^n, {n, 30}] (* or *) CoefficientList[Series[16 (1 + 8 x + 64 x^2)/(1 - 8 x)^4, {x, 0, 20}], x] (* Vincenzo Librandi, Feb 22 2013 *)

Prog

(Magma) [(n^3 + n)*8^n: n in [1..20]]; // Vincenzo Librandi, Feb 22 2013
(Magma) I:=[16, 640, 15360, 278528]; [n le 4 select I[n] else 32*Self(n-1)-384*Self(n-2)+2048*Self(n-3)-4096*Self(n-4): n in [1..20]]; // Vincenzo Librandi, Feb 23 2013

Crossrefs

Cf. A128796, A128960, A128985, A129002.

Sequence in context: A159745 A091496 A139166 * A197670 A162546 A328274

Adjacent sequences: A128045 A128046 A128047 * A128049 A128050 A128051

Keyword

nonn,easy

Author

Mohammad K. Azarian, May 02 2007

Status

approved