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.

A260575 Number of ways to place 2n rooks on n X n board, 2 rooks in each row and each column, multiple rooks in a cell allowed, and exactly 3 rooks below the main diagonal.

Table of values

n a(n)
3 4
4 114
5 1492
6 13992
7 109538
8 769632
9 5050616
10 31702275
11 193204684
12 1154354559
13 6805263818
14 39756392269
15 230829718918
16 1334626765852
17 7694795830792
18 44279453377166
19 254475676808510
20 1461211112505546
21 8385454709982584
22 48102877501302765
23 275868835046218560

List of values

[4, 114, 1492, 13992, 109538, 769632, 5050616, 31702275, 193204684, 1154354559, 6805263818, 39756392269, 230829718918, 1334626765852, 7694795830792, 44279453377166, 254475676808510, 1461211112505546, 8385454709982584, 48102877501302765, 275868835046218560]

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

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