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A145143 1st column of A145142. 2
1, 1, 2, 6, 144, 1200, 9960, 89040, 1231776, 18325440, 280100160, 4415368320, 78497147520, 1538731434240, 32250825734400, 708789321676800, 16531867860480000, 410557135229337600, 10800330695046144000 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,3

LINKS

Table of n, a(n) for n=2..20.

MAPLE

row:= proc(n) option remember; local f, i, x; f:= unapply (simplify (sum ('cat (a||i) *x^i', 'i'=0..n-1) ), x); unapply (subs (solve ({seq(f(i+1)= coeftayl (x/ (1-x-x^4)/ (1-x)^i, x=0, n), i=0..n-1)}, {seq (cat (a||i), i=0..n-1)}), sum ('cat (a||i) *x^i', 'i'=0..n-1) ), x); end: a:= n-> `if` (n=0, 0, coeftayl (row(n)(x), x=0, 1) *(n-1)!): seq (a(n), n=2..23);

MATHEMATICA

row[n_] := row[n] = Module[{f, a, eq}, f = Function[x, Sum[a[k]*x^k, {k, 0, n-1}]]; eq = Table[f[k+1] == SeriesCoefficient[x/(1-x-x^4)/(1-x)^k, {x, 0, n}], {k, 0, n-1}]; List @@ f[1] /. Solve[eq] // First]; a[n_] := row[n][[2]]*(n-1)!; Table[a[n], {n, 2, 23}] (* Jean-Fran├žois Alcover, Feb 14 2014, after Maple *)

CROSSREFS

Cf. A145153.

Sequence in context: A047937 A027731 A280821 * A280378 A280714 A164764

Adjacent sequences:  A145140 A145141 A145142 * A145144 A145145 A145146

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Oct 03 2008

STATUS

approved

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Last modified April 14 12:11 EDT 2021. Contains 342949 sequences. (Running on oeis4.)