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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A350681 Triangle read by rows. T(n,k) is the number of hitomezashi loops of width 2(n-k)+1 and height 2k+1 for 0 <= k <= n.

Original entry on oeis.org

1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 2, 1, 0, 0, 1, 4, 4, 1, 0, 0, 1, 8, 11, 8, 1, 0, 0, 1, 16, 27, 27, 16, 1, 0, 0, 1, 32, 64, 76, 64, 32, 1, 0
Offset: 0

Views

Author

Colin Defant, Jan 11 2022

Keywords

Comments

The Defant--Kravitz paper proves that every hitomezashi loop has odd width and odd height.

Examples

			Triangle T(n,k) begins:
  1;
  0, 0;
  0, 1,  0;
  0, 1,  1,  0;
  0, 1,  2,  1,  0;
  0, 1,  4,  4,  1,  0;
  0, 1,  8, 11,  8,  1,  0;
  0, 1, 16, 27, 27, 16,  1, 0;
  0, 1, 32, 64, 76, 64, 32, 1, 0;
  ...
		

Crossrefs

T(2n,n) gives: A350680.

Formula

T(n,k) = T(n,n-k).
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