A103778 Inverse of trinomial triangle A071675.

1, 0, 1, 0, -1, 1, 0, 1, -2, 1, 0, 0, 3, -3, 1, 0, -4, -2, 6, -4, 1, 0, 14, -7, -7, 10, -5, 1, 0, -30, 36, -6, -16, 15, -6, 1, 0, 33, -96, 63, 3, -30, 21, -7, 1, 0, 55, 154, -209, 88, 25, -50, 28, -8, 1, 0, -429, 0, 429, -374, 99, 66, -77, 36, -9, 1, 0, 1365, -1014

Offset

0,9

Comments

Inverse of Riordan array (1, x(1+x+x^2)) (A071675).

Links

Table of n, a(n) for n=0..68.

Formula

Riordan array (1, y) where y satisfies y + y^2 + y^3 = x; y = -2^(2/3)*((3*sqrt(3)*sqrt(27*x^2 + 14*x + 3) - 27*x - 7)^(1/3) - (3*sqrt(3)*sqrt(27*x^2 + 14*x + 3) + 27*x + 7)^(1/3) + 2^(1/3))/6.

Example

Rows start
{1},
{0,1},
{0,-1,1},
{0,1,-2,1},
{0,0,3,-3,1},
...

Crossrefs

Cf. A071675.

Sequence in context: A221833 A319082 A034365 * A099423 A221515 A221984

Adjacent sequences: A103775 A103776 A103777 * A103779 A103780 A103781

Keyword

easy,sign,tabl

Author

Paul Barry, Feb 15 2005

Status

approved