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A292752
Dimensions of centralizer algebras of groups associated with Z_4-codes.
1
1, 1, 3, 16, 108, 811, 6513, 54706, 472818, 4157701, 36931023, 329937796, 2957233128, 26554062991, 238681391133, 2146606641286, 19311830377038, 173768326420681, 1563724202922843, 14072564151989176, 126648308996320548, 1139810939108974771, 10258179242691222153, 92323017137773245466
OFFSET
0,3
REFERENCES
M. Kosuda and M. Oura, Centralizer algebras of the group associated to Z_4-codes, Discrete Math., 340 (2017), 2437-2446.
LINKS
M. Kosuda and M. Oura, Centralizer algebras of the group associated to Z_4-codes, arXiv:1608.08731 [math.RT], 2016-2017.
FORMULA
For n>0, a(n) = (57+6*5^n+9^n)/96.
From Colin Barker, Sep 25 2017: (Start)
G.f.: (1 - 14*x + 47*x^2 - 15*x^3) / ((1 - x)*(1 - 5*x)*(1 - 9*x)).
a(n) = 15*a(n-1) - 59*a(n-2) + 45*a(n-3) for n>3.
(End)
PROG
(PARI) a(n) = if (n==0, 1, (57+6*5^n+9^n)/96); \\ Michel Marcus, Sep 25 2017
(PARI) Vec((1 - 14*x + 47*x^2 - 15*x^3) / ((1 - x)*(1 - 5*x)*(1 - 9*x)) + O(x^30)) \\ Colin Barker, Sep 25 2017
CROSSREFS
Sequence in context: A369694 A074551 A135074 * A220379 A191800 A286764
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Sep 24 2017
EXTENSIONS
More terms from Michel Marcus, Sep 25 2017
STATUS
approved