A049127 Revert transform of (-1 + 2x + x^2)/(-1 + x + 2x^2 + x^3).

1, 1, 2, 6, 22, 88, 369, 1597, 7078, 31966, 146592, 680826, 3195883, 15138737, 72274885, 347411257, 1679958814, 8166820486, 39889343392, 195658510368, 963381098208, 4759922215444, 23592260956562, 117270856692388

Offset

1,3

Links

Table of n, a(n) for n=1..24.

Index entries for reversions of series

Formula

Recurrence: 8*(n-1)*n*(79*n - 153)*a(n) = 2*(n-1)*(2370*n^2 - 7829*n + 6225)*a(n-1) - (7663*n^3 - 41385*n^2 + 69515*n - 34773)*a(n-2) + (n-3)*(1106*n^2 - 1352*n - 789)*a(n-3) + 31*(n-4)*(n-3)*(79*n - 74)*a(n-4). - Vaclav Kotesovec, Jan 02 2021

Mathematica

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

Crossrefs

Sequence in context: A165539 A109033 A049135 * A199481 A049137 A287223

Adjacent sequences: A049124 A049125 A049126 * A049128 A049129 A049130

Keyword

nonn

Author

Olivier Gérard

Status

approved