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.

A272070 Number of ways to quarter a 2n+1 X 2n+1 chessboard with central square removed.

Table of values

n a(n)
0 1
1 1
2 7
3 104
4 3970
5 431932
6 137066448
7 128095791922
8 355704307903818
9 2952926822418475378
10 73569487283165427567144
11 5515501712040561162370942752
12 1246743475892797935712690352483842
13 850999652841310762943520023896881419780

List of values

[1, 1, 7, 104, 3970, 431932, 137066448, 128095791922, 355704307903818, 2952926822418475378, 73569487283165427567144, 5515501712040561162370942752, 1246743475892797935712690352483842, 850999652841310762943520023896881419780]

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

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