cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A320902 Expansion of ogf(x, t) = u / (6*x - t*x*u - 2) with u = x*(2*x - 2*y + 8) + y - 3 and y = sqrt(1 - 4*x). Triangle read by rows: T(n, k) with 0 <= k <= n.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 3, 3, 3, 1, 4, 6, 8, 10, 1, 5, 10, 16, 27, 34, 1, 6, 15, 28, 54, 94, 116, 1, 7, 21, 45, 95, 192, 329, 396, 1, 8, 28, 68, 155, 344, 688, 1152, 1353, 1, 9, 36, 98, 240, 571, 1260, 2466, 4034, 4631, 1, 10, 45, 136, 357, 900, 2135, 4616, 8832, 14136, 15895
Offset: 0

Views

Author

Peter Luschny, Oct 23 2018

Keywords

Examples

			Triangle starts:
[0] [1]
[1] [1, 1]
[2] [1, 2,  1]
[3] [1, 3,  3,  3]
[4] [1, 4,  6,  8,  10]
[5] [1, 5, 10, 16,  27,  34]
[6] [1, 6, 15, 28,  54,  94,  116]
[7] [1, 7, 21, 45,  95, 192,  329,  396]
[8] [1, 8, 28, 68, 155, 344,  688, 1152, 1353]
[9] [1, 9, 36, 98, 240, 571, 1260, 2466, 4034, 4631]
		

Crossrefs

Row sums are A320903.

Programs

  • Maple
    X := 10: f := x -> 3/2 + (x - sqrt(1 - 4*x))*(2*x - 1)/(6*x - 2):
    ogf := (x, t) -> f(x)/(1 - t*x*f(x)): ser := series(ogf(x, t), x, X+1):
    row := n -> PolynomialTools:-CoefficientList(coeff(ser, x, n), t, 'termorder' = 'reverse'): ListTools:-Flatten([seq(row(n), n=0..X)]);