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.

A290279 Number of permutations of [n] with a unique pair of orthogonal (diagonal, antidiagonal) X-rays.

Table of values

n a(n)
0 1
1 1
2 2
3 6
4 22
5 110
6 628
7 4396
8 34496
9 309230
10 3069808

List of values

[1, 1, 2, 6, 22, 110, 628, 4396, 34496, 309230, 3069808]