A030279 COMPOSE squares with squares.

1, 8, 50, 276, 1397, 6672, 30565, 135668, 587426, 2493056, 10407393, 42848800, 174348417, 702245128, 2803634370, 11106624804, 43697519013, 170871040752, 664492915061, 2571316718500, 9905232077842, 38000679280352, 145240335213857, 553203971301184, 2100403987129441, 7951405959127848

Offset

1,2

Links

Table of n, a(n) for n=1..26.

N. J. A. Sloane, Transforms

Index entries for linear recurrences with constant coefficients, signature (12, -54, 115, -132, 108, -59, 24, -6, 1).

Formula

G.f.: ((1-x)^3*(1+x)*(1-2*x+4*x^2-x^3))/((1-4*x+2*x^2-x^3)^3).

a(n) = 12*a(n-1)-54*a(n-2)+115*a(n-3)-132*a(n-4)+108*a(n-5)-59*a(n-6)+24*a(n-7)-6*a(n-8)+a(n-9). - Wesley Ivan Hurt, Apr 23 2021

Mathematica

CoefficientList[Series[((1-x)^3(1+x)(1-2x+4x^2-x^3))/((1-4x+2x^2-x^3)^3), {x, 0, 30}], x] (* or *) LinearRecurrence[{12, -54, 115, -132, 108, -59, 24, -6, 1}, {1, 8, 50, 276, 1397, 6672, 30565, 135668, 587426}, 30] (* Harvey P. Dale, Mar 14 2016 *)

Prog

(PARI) Vec(((1-x)^3*(1+x)*(1-2*x+4*x^2-x^3))/((1-4*x+2*x^2-x^3)^3)+O(x^66)) \\ Joerg Arndt, Apr 21 2013

Crossrefs

Cf. A000290, A030267, A279282.

Sequence in context: A290617 A163228 A033463 * A133357 A081675 A283277

Adjacent sequences: A030276 A030277 A030278 * A030280 A030281 A030282

Keyword

nonn,nice,easy

Author

Christian G. Bower

Status

approved