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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.
2
1, 6, 66, 714, 7710, 83226, 898350, 9696810, 104667486, 1129781946, 12194877966, 131631637962, 1420833250878, 15336488688474, 165542216262126, 1786864380862314, 19287432460962078, 208188743880291834, 2247191437542514638, 24256207433904571146, 261821751919823278590
OFFSET
1,2
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
MATHEMATICA
LinearRecurrence[{11, 0, -24}, {1, 6, 66, 714}, 30] (* G. C. Greubel, Feb 14 2021 *)
PROG
(Sage)
def A131519_list(prec):
P.<x> = 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
(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
CROSSREFS
Previously this sequence was thought to represent what now is A354228.
Sequence in context: A186673 A213453 A186671 * A373816 A022024 A186666
KEYWORD
nonn
AUTHOR
Yasutoshi Kohmoto, Aug 15 2007, Oct 03 2007
EXTENSIONS
More terms from Max Alekseyev, Sep 29 2007
Edited by Max Alekseyev, Jul 18 2022
STATUS
approved