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.

A054514 Number of ways to place non-crossing diagonals in convex (n+4)-gon so as to create no triangles or quadrilaterals.

Table of values

n a(n)
1 1
2 1
3 1
4 5
5 10
6 16
7 45
8 109
9 222
10 540
11 1341
12 3065
13 7328
14 18112
15 43530
16 105390
17 260254
18 639244
19 1570257
20 3893805
21 9669236
22 24014264
23 59903650
24 149806494
25 374982790
26 940835404
27 2365679689
28 5955973237
29 15018854005
30 37935575685
31 95942896837
32 242954350457
33 616034170069
34 1563810857705
35 3974000543475

List of values

[1, 1, 1, 5, 10, 16, 45, 109, 222, 540, 1341, 3065, 7328, 18112, 43530, 105390, 260254, 639244, 1570257, 3893805, 9669236, 24014264, 59903650, 149806494, 374982790, 940835404, 2365679689, 5955973237, 15018854005, 37935575685, 95942896837, 242954350457, 616034170069, 1563810857705, 3974000543475]

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

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