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.

A278721 Number of nX2 0..3 arrays with rows in nondecreasing lexicographic order and columns in nonincreasing lexicographic order.

Table of values

n a(n)
1 10
2 60
3 275
4 1050
5 3492
6 10401
7 28288
8 71266
9 168155
10 374868
11 795158
12 1614184
13 3151188
14 5939970
15 10848924
16 19256291
17 33301148
18 56236656
19 92919425
20 150477730
21 239211960
22 373793355
23 574842060
24 870983100
25 1301499381
26 1919724600

List of values

[10, 60, 275, 1050, 3492, 10401, 28288, 71266, 168155, 374868, 795158, 1614184, 3151188, 5939970, 10848924, 19256291, 33301148, 56236656, 92919425, 150477730, 239211960, 373793355, 574842060, 870983100, 1301499381, 1919724600]