A025983 Expansion of 1/((1-2*x)*(1-4*x)*(1-10*x)*(1-11*x)).

1, 27, 485, 7335, 101181, 1319967, 16597525, 203384295, 2445473261, 28983189807, 339647023365, 3944444998455, 45472205947741, 521027509282047, 5939635577526005, 67419323254471815, 762445883405916621, 8595238027891956687, 96630951548518953445, 1083773800000538076375

Offset

0,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..900

Index entries for linear recurrences with constant coefficients, signature (27,-244,828,-880).

Formula

a(n) = -2^n/18+16*4^n/21-125*10^n/6+1331*11^n/63. - R. J. Mathar, Jun 20 2013

a(n) = (4^(n+1)-2^(n+1))/2+21*a(n-1)-110*a(n-2). - Vincenzo Librandi, Jul 03 2026

Mathematica

CoefficientList[Series[1/((1-2x)(1-4x)(1-10x)(1-11x)), {x, 0, 20}], x] (* Harvey P. Dale, Aug 11 2019 *)
(* Alternative: *)
a[0]=1; a[1]=27; Do[a[n]=(4^(n+1)-2^(n+1))/2+21*a[n-1]-110*a[n-2], {n, 2, 22}]; Table[a[n], {n, 0, 19}] (* Vincenzo Librandi, Jul 03 2026 *)

Prog

(Magma) I:=[1, 27]; [n le 2 select I[n] else (4^n-2^n)/2+21*Self(n-1)-110*Self(n-2): n in [1..20]]; // Vincenzo Librandi, Jul 03 2026

Crossrefs

Sequence in context: A024439 A026006 A024346 * A081139 A020976 A024114

Adjacent sequences: A025980 A025981 A025982 * A025984 A025985 A025986

Keyword

nonn,easy,changed

Author

N. J. A. Sloane

Extensions

More terms from Vincenzo Librandi, Jul 03 2026

Status

approved