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.

A047858 T(n, k) = 2^(k-1)*(k + 2*n) - n + 1, array read by descending antidiagonals.

Original entry on oeis.org

1, 2, 1, 5, 3, 1, 13, 8, 4, 1, 33, 20, 11, 5, 1, 81, 48, 27, 14, 6, 1, 193, 112, 63, 34, 17, 7, 1, 449, 256, 143, 78, 41, 20, 8, 1, 1025, 576, 319, 174, 93, 48, 23, 9, 1, 2305, 1280, 703, 382, 205, 108, 55, 26, 10, 1, 5121, 2816, 1535, 830, 445, 236, 123, 62, 29, 11, 1
Offset: 0

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Keywords

Comments

Previous name was: Array T read by diagonals; n-th difference of (T(k,n),T(k,n-1),...,T(k,0)) is k+n, for n=1,2,3,...; k=0,1,2,...

Examples

			From _Stefano Spezia_, Jan 03 2023: (Start)
The array begins:
  1, 2,  5, 13,  33,  81,...
  1, 3,  8, 20,  48, 112,...
  1, 4, 11, 27,  63, 143,...
  1, 5, 14, 34,  78, 174,...
  1, 6, 17, 41,  93, 205,...
  1, 7, 20, 48, 108, 236,...
  ...
(End)
		

Crossrefs

Row 1 = (1, 2, 5, 13, 33, ...) = A005183.
Row 2 = (1, 3, 8, 20, 48, ...) = A001792.

Programs

  • Mathematica
    T[n_,k_]:=2^(k-1)*(k+2n)-n+1;Table[Reverse[Table[T[n-k,k],{k,0,n}]],{n,0,10}]//Flatten (* Stefano Spezia, Jan 02 2023 *)

Formula

T(n, k) = 2^(k-1)*(k + 2*n) - n + 1. - Benoit Cloitre, Jun 17 2003
G.f.: (1 - x - 3*y + 4*x*y + 3*y^2 - 5*x*y^2)/((1 - x)^2*(1 - 2*y)^2*(1 - y)). - Stefano Spezia, Jan 02 2023

Extensions

New name using formula by Benoit Cloitre, Joerg Arndt, Jan 03 2023