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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.

A200987 Number of nX5 0..4 arrays with every row and column nondecreasing rightwards and downwards, and the number of instances of each value within one of each other.

Table of values

n a(n)
1 1
2 21
3 140
4 1095
5 4919
6 27000
7 97341
8 383172
9 1188521
10 3704820
11 9947816
12 27240277
13 65292069
14 157646021
15 349738426
16 770969390
17 1585648871
18 3256248216
19 6303135880
20 12177430692
21 22459794938
22 41128002746
23 72582886199
24 127586136583

List of values

[1, 21, 140, 1095, 4919, 27000, 97341, 383172, 1188521, 3704820, 9947816, 27240277, 65292069, 157646021, 349738426, 770969390, 1585648871, 3256248216, 6303135880, 12177430692, 22459794938, 41128002746, 72582886199, 127586136583]

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement.