A049129 Revert transform of (3x^2 - 1)/(-1 - x + 2x^2 + x^3).

1, 1, 2, 6, 20, 72, 271, 1055, 4212, 17152, 70966, 297482, 1260715, 5392627, 23251149, 100947165, 440939300, 1936388032, 8544353718, 37863744762, 168438633954, 751927422662, 3367361700052, 15123922285632, 68107641527359

Offset

1,3

Links

Table of n, a(n) for n=1..25.

Index entries for reversions of series

Formula

Recurrence: 36*(n-1)*n*(7372*n^2 - 45117*n + 67172)*a(n) = 12*(n-1)*(81092*n^3 - 606867*n^2 + 1412200*n - 999768)*a(n-1) + (1540748*n^4 - 16034765*n^3 + 61923424*n^2 - 104990155*n + 65807196)*a(n-2) - (302252*n^4 - 2594369*n^3 + 7923316*n^2 - 10164511*n + 4599084)*a(n-3) - 7*(n-4)*(169556*n^3 - 1524243*n^2 + 4084408*n - 3312093)*a(n-4) + 49*(n-5)*(n-4)*(7372*n^2 - 30373*n + 29427)*a(n-5). - Vaclav Kotesovec, Jan 02 2021

Mathematica

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

Crossrefs

Sequence in context: A216837 A192658 A049141 * A063376 A161168 A049139

Adjacent sequences: A049126 A049127 A049128 * A049130 A049131 A049132

Keyword

nonn

Author

Olivier Gérard

Status

approved