A229463 Expansion of 1/((1-x)^2*(1-26*x)).

1, 28, 731, 19010, 494265, 12850896, 334123303, 8687205886, 225867353045, 5872551179180, 152686330658691, 3969844597125978, 103215959525275441, 2683614947657161480, 69773988639086198495, 1814123704616241160886, 47167216320022270183053

Offset

0,2

Comments

This sequence was chosen to illustrate a method of solution.

Links

Table of n, a(n) for n=0..16.

Index entries for linear recurrences with constant coefficients, signature (28, -53, 26).

Formula

a(n) = (26^(n+2) - 25*n - 51)/625.

In general, for the expansion of 1/((1-s*x)^2*(1-r*x)) with r>s>=1 we have the formula: a(n) = (r^(n+2)- s^(n+1)*((r-s)*n +(2*r-s)))/(r-s)^2.

Example

a(3) = (26^5 - 25*3 - 51)/625 = 19010.

Crossrefs

Cf. A000295, A000340, A014825, A014827, A014936,

Sequence in context: A012808 A226991 A277060 * A097834 A162830 A163187

Adjacent sequences: A229460 A229461 A229462 * A229464 A229465 A229466

Keyword

nonn

Author

Yahia Kahloune, Sep 24 2013

Status

approved