A145145 3rd column of A145142.

1, 6, 35, 225, 2464, 29932, 375164, 4877100, 73016856, 1229669496, 22393143552, 430226343456, 8838633396384, 195021406776960, 4592633620285440, 114230969866103040, 2991995263667137536, 82505359191832358400

Offset

4,2

Links

Table of n, a(n) for n=4..21.

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, 3) *(n-1)!): seq (a(n), n=4..25);

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][[4]]*(n-1)!; Table[a[n], {n, 4, 25}] (* Jean-François Alcover, Feb 14 2014, after Maple *)

Crossrefs

Cf. A145153.

Sequence in context: A357834 A000399 A081051 * A367234 A357828 A347002

Adjacent sequences: A145142 A145143 A145144 * A145146 A145147 A145148

Keyword

nonn

Author

Alois P. Heinz, Oct 03 2008

Status

approved