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.

A257887 Number of proper diagonals of the n-dimensional associahedron (i.e., diagonals that are not included in lower dimension faces).

Table of values

n a(n)
1 1
2 5
3 34
4 273
5 2436
6 23391
7 237090
8 2505228
9 27360612
10 306956091
11 3521389998
12 41164654020
13 489017000736
14 5890746106977
15 71829149873286
16 885296835708778
17 11015753148497480
18 138241674405266782
19 1748203287998505712
20 22261537862360050040
21 285268915333307553016

List of values

[1, 5, 34, 273, 2436, 23391, 237090, 2505228, 27360612, 306956091, 3521389998, 41164654020, 489017000736, 5890746106977, 71829149873286, 885296835708778, 11015753148497480, 138241674405266782, 1748203287998505712, 22261537862360050040, 285268915333307553016]

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

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