A131519 a(1) = 1, a(2) = 6, a(3) = 66, a(4) = 714, and a(n) = 11*a(n-1) - 24*a(n-3) for n >= 5.

1, 6, 66, 714, 7710, 83226, 898350, 9696810, 104667486, 1129781946, 12194877966, 131631637962, 1420833250878, 15336488688474, 165542216262126, 1786864380862314, 19287432460962078, 208188743880291834, 2247191437542514638, 24256207433904571146, 261821751919823278590

Offset: 1

Author

Yasutoshi Kohmoto, Aug 15 2007, Oct 03 2007

Keywords

• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 1..950
• Index entries for linear recurrences with constant coefficients, signature (11, 0, -24).

Crossrefs

Previously this sequence was thought to represent what now is A354228.

Programs

Magma

I:=[6, 66, 714]; [1] cat [n le 3 select I[n] else 11*Self(n-1) -24*Self(n-3): n in [1..30]]; // G. C. Greubel, Feb 14 2021

Mathematica

LinearRecurrence[{11, 0, -24}, {1, 6, 66, 714}, 30] (* G. C. Greubel, Feb 14 2021 *)

Sage

def A131519_list(prec):
    P. = PowerSeriesRing(ZZ, prec)
    return P( x*(1-2*x)*(1-3*x-6*x^2)/(1-11*x+24*x^3) ).list()
a=A131519_list(31); a[1:] # G. C. Greubel, Feb 14 2021

Formula

For n>4, a(n) = 11*a(n-1) - 24*a(n-3). - Max Alekseyev, Sep 29 2007

G.f.: x*(1-2*x)*(1-3*x-6*x^2)/(1-11*x+24*x^3). - R. J. Mathar, Nov 14 2007

Extensions

More terms from Max Alekseyev, Sep 29 2007

Edited by Max Alekseyev, Jul 18 2022