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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A223838 T(n,k) = number of n X k 0..1 arrays with rows, diagonals and antidiagonals unimodal and columns nondecreasing.

Original entry on oeis.org

2, 4, 3, 7, 9, 4, 11, 22, 16, 5, 16, 46, 48, 25, 6, 22, 86, 118, 89, 36, 7, 29, 148, 255, 249, 149, 49, 8, 37, 239, 503, 596, 471, 232, 64, 9, 46, 367, 926, 1286, 1240, 824, 342, 81, 10, 56, 541, 1614, 2578, 2884, 2388, 1356, 483, 100, 11, 67, 771, 2690, 4886, 6159, 5992
Offset: 1

Views

Author

R. H. Hardin, Mar 27 2013

Keywords

Examples

			Table starts:
   2   4   7   11    16    22     29     37      46      56      67       79
   3   9  22   46    86   148    239    367     541     771    1068     1444
   4  16  48  118   255   503    926   1614    2690    4318    6712    10146
   5  25  89  249   596  1286   2578   4886    8851   15439   26072    42800
   6  36 149  471  1240  2884   6159  12371   23716   43790   78342   136368
   7  49 232  824  2388  5992  13582  28642   57306  110164  205131   371923
   8  64 342 1356  4325 11749  28369  62869  130891  260219  499470   932402
   9  81 483 2123  7436 21912  56607 132427  287719  591705 1167798  2233350
  10 100 659 3189 12222 39064 108282 268624  611901 1306407 2655964  5202806
  11 121 874 4626 19316 66854 199047 525323 1260152 2805670 5897718 11863338
  ...
Some solutions for n=3 k=4:
..1..0..0..0....0..1..0..0....0..0..0..0....0..0..0..0....0..1..1..0
..1..1..0..0....1..1..1..0....0..0..0..1....0..0..0..0....0..1..1..0
..1..1..0..0....1..1..1..1....0..0..1..1....1..1..1..1....0..1..1..0
		

Crossrefs

Main diagonal is A223832.
Columns 1..7 are A000027(n+1), A000290(n+1), A223833, A223834, A223835, A223836, A223837.

Formula

Empirical columns k=1..7 are polynomials of degree k for n>0,0,0,1,2,3,4.
Empirical rows n=1..7 are polynomials of degree 2*n for k>0,0,0,2,4,6,8.

Extensions

Name corrected by Andrew Howroyd, Mar 18 2025
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