A049131 Revert transform of (1 + 2x - x^2)/(1 + 3x + 2x^2 + x^3).

1, 1, 2, 4, 10, 24, 65, 171, 482, 1338, 3868, 11110, 32707, 96137, 287001, 857577, 2588794, 7830730, 23854028, 72840384, 223557060, 687811608, 2124300494, 6576110024, 20418808851, 63534855143, 198178318008, 619338524116

Offset

1,3

Links

Table of n, a(n) for n=1..28.

Index entries for reversions of series

Formula

Recurrence: 8*(n-1)*n*(79*n - 186)*a(n) = - 2*(n-1)*(474*n^2 - 1669*n + 1510)*a(n-1) + (5293*n^3 - 33792*n^2 + 74125*n - 56126)*a(n-2) + (12719*n^3 - 97096*n^2 + 242641*n - 190562)*a(n-3) + (n-4)*(8927*n^2 - 44244*n + 45159)*a(n-4) + 23*(n-5)*(n-4)*(79*n - 107)*a(n-5). - Vaclav Kotesovec, Jan 02 2021

Mathematica

Rest[CoefficientList[InverseSeries[Series[x*(1 + 2x - x^2)/(1 + 3x + 2x^2 + x^3), {x, 0, 40}], x], x]] (* Vaclav Kotesovec, Jan 02 2021 *)

Crossrefs

Sequence in context: A049144 A354733 A336419 * A084078 A137842 A049146

Adjacent sequences: A049128 A049129 A049130 * A049132 A049133 A049134

Keyword

nonn

Author

Olivier Gérard

Status

approved