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.

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A178304 Triangle T(n,m) = 1 + f(n+1)*(f(m+1) + f(n-m+1) - 1 - f(n+1)), read by rows, where f(.)=A002487(.).

Original entry on oeis.org

1, 1, 1, 1, -1, 1, 1, 2, 2, 1, 1, -5, 1, -5, 1, 1, 3, 1, 1, 3, 1, 1, -2, 4, -5, 4, -2, 1, 1, 3, 3, 3, 3, 3, 3, 1, 1, -11, 1, -7, 5, -7, 1, -11, 1, 1, 4, -2, 1, 4, 4, 1, -2, 4, 1, 1, -9, 1, -19, 1, -9, 1, -19, 1, -9, 1
Offset: 0

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Author

Roger L. Bagula and Gary W. Adamson, May 24 2010

Keywords

Comments

Row sums are 1, 2, 1, 6, -7, 10, 1, 20, -27, 16, -59, ...

Examples

			Rows n >= 0, 0 <= k <= n begin
  1;
  1,   1;
  1,  -1,   1;
  1,   2,   2,   1;
  1,  -5,   1,  -5,   1;
  1,   3,   1,   1,   3,   1;
  1,  -2,   4,  -5,   4,  -2,   1;
  1,   3,   3,   3,   3,   3,   3,   1;
  1, -11,   1,  -7,   5,  -7,   1, -11,   1;
  1,   4,  -2,   1,   4,   4,   1,  -2,   4,   1;
  1,  -9,   1, -19,   1,  -9,   1, -19,   1,  -9,   1;
		

Crossrefs

Programs

  • Maple
    A002487 := proc(n) option remember; if n <=1 then n; else if type(n,'even') then procname(n/2) ; else procname((n-1)/2)+procname(1+(n-1)/2) ; end if; end if; end proc:
    A178304 := proc(n,m) 1 + A002487(n+1)*( A002487(m+1)+A002487(n-m+1)-1-A002487(n+1) ) ; end proc:
    seq(seq(A178304(n,k),k=0..n),n=0..15) ; # N. J. A. Sloane, Jul 20 2010
  • Mathematica
    a[0] = 0; a[1] = 1;
    a[n_] := a[n] = If[Mod[n, 2] == 0, a[Floor[n/2]], a[ Floor[(n - 1)/2]] + a[Floor[(n + 1)/2]]];
    tg[n_, m_] := 1 + a[n + 1]*a[m + 1] + a[n + 1]*a[n - m + 1] - (a[n + 1]*a[ 0 + 1] + a[n + 1]*a[n - 0 + 1]);
    Table[Table[tg[n, m], {m, 0, n}], {n, 0, 10}];
    Flatten[%]

Extensions

Definition simplified by the Assoc. Eds. of the OEIS, Jul 20 2010
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