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.

A177947 A symmetrical triangle sequence based on the beta function inverse and the spotlight tile A051601 as antidiagonal: t(n,m) = 1/Integrate[(-1 + t)^n/t^(m + n + 2), {t, 1, Infinity}] - (-2 Binomial[m + n, m] + Binomial[2 + m + n, 1 + m]).

Original entry on oeis.org

1, 1, 1, 1, 4, 1, 1, 8, 8, 1, 1, 13, 22, 13, 1, 1, 19, 45, 45, 19, 1, 1, 26, 79, 110, 79, 26, 1, 1, 34, 126, 224, 224, 126, 34, 1, 1, 43, 188, 406, 518, 406, 188, 43, 1, 1, 53, 267, 678, 1050, 1050, 678, 267, 53, 1
Offset: 0

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Author

Roger L. Bagula, May 15 2010

Keywords

Comments

Beta[n+1,m+1] = Integrate[(-1 + t)^n/t^(m + n + 2), {t, 1, Infinity}].
Row sums are {1, 2, 6, 18, 50, 130, 322, 770, 1794, 4098, ...}.
The triangle modulo 2 is Sierpinski:
ListDensityPlot[Table[Table[Mod[ t[n, m], 2], {m, 0, 64}], {n, 0, 64}], Frame -> False, Mesh -> False].

Examples

			{1},
{1, 1},
{1, 4, 1},
{1, 8, 8, 1},
{1, 13, 22, 13, 1},
{1, 19, 45, 45, 19, 1},
{1, 26, 79, 110, 79, 26, 1},
{1, 34, 126, 224, 224, 126, 34, 1},
{1, 43, 188, 406, 518, 406, 188, 43, 1},
{1, 53, 267, 678, 1050, 1050, 678, 267, 53, 1}
		

Crossrefs

Programs

  • Mathematica
    Clear[t, n]
    t[n_, m_] = 1/Integrate[(-1 + t)^n/t^(m + n + 2), {t, 1, Infinity}] - (-2 Binomial[m + n, m] + Binomial[2 + m + n, 1 + m]);
    a = Table[Table[t[n, m], {n, 0, 10}], {m, 0, 10}];
    Table[Table[a[[m, n - m + 1]], {m, 1, n}], {n, 1, 10}];
    Flatten[%]

Formula

t(n,m) = 1/Integrate[(-1 + t)^n/t^(m + n + 2), {t, 1, Infinity}] - (-2 Binomial[m + n, m] + Binomial[2 + m + n, 1 + m]);
out_n,m = antidiagonal(t(n,m)) = A003506(n,m) - A051601(n,m).