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.

A152173 a(n) is the number of Dyck paths of length n without height of peaks 1 (mod 3) and height of valleys 2 (mod 3).

Table of values

n a(n)
2 1
3 0
4 1
5 2
6 4
7 10
8 23
9 56
10 138
11 344
12 870
13 2220
14 5716
15 14828
16 38717
17 101682
18 268416
19 711810
20 1895432
21 5066030
22 13586082
23 36547534
24 98593064
25 266661162
26 722953814
27 1964358938
28 5348367006
29 14589803090
30 39870312218
31 109136843138

List of values

[1, 0, 1, 2, 4, 10, 23, 56, 138, 344, 870, 2220, 5716, 14828, 38717, 101682, 268416, 711810, 1895432, 5066030, 13586082, 36547534, 98593064, 266661162, 722953814, 1964358938, 5348367006, 14589803090, 39870312218, 109136843138]

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

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