A028026 Expansion of 1/((1-3x)(1-4x)(1-5x)(1-7x)).

1, 19, 230, 2270, 19971, 163569, 1278040, 9670540, 71557541, 521211119, 3754036650, 26822296410, 190541788711, 1347984742669, 9507913700060, 66919750327880, 470277075161481, 3301201972518219, 23154999755212270, 162319024049252950, 1137407684744763851

Offset

0,2

Links

Table of n, a(n) for n=0..20.

Index entries for linear recurrences with constant coefficients, signature (19,-131,389,-420).

Formula

a(n) = (7^(n+3)-6*5^(n+3)+8*4^(n+3)-3^(n+4))/24. - Yahia Kahloune, May 22 2013

E.g.f.: exp(3*x)*(-81 + 512*exp(x) - 750*exp(2*x) + 343*exp(4*x))/24. - Stefano Spezia, Nov 24 2025

Mathematica

CoefficientList[Series[1/((1-3x)(1-4x)(1-5x)(1-7x)), {x, 0, 20}], x] (* Harvey P. Dale, Apr 05 2019 *)

Crossrefs

Sequence in context: A243420 A125431 A104116 * A135487 A025965 A276201

Adjacent sequences: A028023 A028024 A028025 * A028027 A028028 A028029

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved