A145144 2nd column of A145142.

1, 3, 11, 50, 634, 6804, 71868, 789984, 11025936, 174509280, 2940903360, 51707242080, 987781034304, 20520063789120, 456583392034560, 10712403843563520, 265316096850923520, 6948996535924162560

Offset

3,2

Links

Table of n, a(n) for n=3..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, 2) *(n-1)!): seq (a(n), n=3..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][[3]]*(n-1)!; Table[a[n], {n, 3, 23}] (* Jean-François Alcover, Feb 14 2014, after Maple *)

Crossrefs

Cf. A145153.

Sequence in context: A024335 A203009 A024336 * A367560 A284702 A191341

Adjacent sequences: A145141 A145142 A145143 * A145145 A145146 A145147

Keyword

nonn

Author

Alois P. Heinz, Oct 03 2008

Status

approved