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A123006 Expansion of x^2/(1-2*x-121*x^2). 0
0, 1, 2, 125, 492, 16109, 91750, 2132689, 15367128, 288789625, 2437001738, 39817548101, 374512306500, 5566947933221, 56449884952942, 786500469825625, 8403437018957232, 111973430886815089, 1240762741067455250 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..19.

MATHEMATICA

(* coefficient expansion*) l = 2; m = 11; p[x_] := -1 - l*x/m + x^2 q[x_] := ExpandAll[x^2*p[1/x]] Table[ SeriesCoefficient[ Series[x/q[x], {x, 0, 30}], n]*m^(n - 1), {n, 0, 30}] (* Binet/ recursion *) f[n_Integer] = Module[{a}, a[n] /. RSolve[{a[n] == l*a[n - 1]/m + a[n - 2], a[0] == 0, a[1] == 1}, a[n], n][[1]] // FullSimplify] ; a = Table[Rationalize[N[f[n]*m^(n - 1), 100], 0], {n, 0, 25}]

CROSSREFS

Cf. A002534.

Sequence in context: A012870 A183720 A042921 * A028481 A049659 A209602

Adjacent sequences:  A123003 A123004 A123005 * A123007 A123008 A123009

KEYWORD

nonn

AUTHOR

Roger L. Bagula and Gary W. Adamson, Sep 23 2006

STATUS

approved

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Last modified June 16 05:18 EDT 2019. Contains 324145 sequences. (Running on oeis4.)