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.

A137645 a(n) = Sum_{k=0..n} C((n-k)*k, k) * C((n-k)*k, n-k).

Table of values

n a(n)
0 1
1 0
2 1
3 4
4 42
5 608
6 10986
7 240492
8 6167112
9 181154848
10 5995624710
11 220711502648
12 8943846698096
13 395588177834784
14 18962600075658460
15 979198125493716492
16 54189002212286942316
17 3199366560075461850320
18 200730550064907653703510
19 13336507142191259122442532
20 935401326531455246646557760
21 69066745767857553528070539760
22 5355032622687046432711489319940

List of values

[1, 0, 1, 4, 42, 608, 10986, 240492, 6167112, 181154848, 5995624710, 220711502648, 8943846698096, 395588177834784, 18962600075658460, 979198125493716492, 54189002212286942316, 3199366560075461850320, 200730550064907653703510, 13336507142191259122442532, 935401326531455246646557760, 69066745767857553528070539760, 5355032622687046432711489319940]

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

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