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.

A176505 Triangle T(n,m) read by rows: T(n,m) = a(n) - a(m) - a(n-m) + 1, where a(n) = A000931(n+4).

Original entry on oeis.org

1, 1, 1, 1, 0, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 2, 2, 2, 2, 1, 1, 1, 1, 2, 3, 2, 3, 2, 1, 1, 1, 2, 3, 4, 4, 4, 4, 3, 2, 1, 1, 2, 4, 5, 5, 6, 5, 5, 4, 2, 1
Offset: 0

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Author

Roger L. Bagula, Apr 19 2010

Keywords

Examples

			Triangle:
{1},
{1, 1},
{1, 0, 1},
{1, 0, 0, 1},
{1, 1, 1, 1, 1},
{1, 0, 1, 1, 0, 1},
{1, 1, 1, 2, 1, 1, 1},
{1, 1, 2, 2, 2, 2, 1, 1},
{1, 1, 2, 3, 2, 3, 2, 1, 1},
{1, 2, 3, 4, 4, 4, 4, 3, 2, 1},
{1, 2, 4, 5, 5, 6, 5, 5, 4, 2, 1},
...
T(6,3) = a(6) - a(3) - a(6-3) + 1 = a(6) - 2 * a(3) + 1 = 3 - (2 * 1) + 1 = 2. - _Indranil Ghosh_, Feb 17 2017
		

Crossrefs

Cf. A000931.

Programs

  • Mathematica
    a[0] := 0; a[1] := 1; a[2] := 1;
    a[n_] := a[n] = a[n - 2] + a[n - 3];
    t[n_, m_] := t[n, m] = a[n] - a[m] - a[n - m] + 1;
    Table[Table[t[n, m], {m, 0, n}], {n, 0, 10}];
    Flatten[%]

Formula

T(n,m) = a(n) - a(m) - a(n-m) + 1, a(n) = A000931(n+4).

Extensions

Name and formula sections corrected by Indranil Ghosh, Feb 17 2017