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.

A069440 Half the number of n X 2 binary arrays with no path of adjacent 1's or adjacent 0's from top row to bottom row.

Table of values

n a(n)
1 0
2 2
3 16
4 88
5 414
6 1810
7 7616
8 31376
9 127710
10 516170
11 2077552
12 8341288
13 33440190
14 133941922
15 536205056
16 2145876128
17 8586053694
18 34350369050
19 137416333936
20 549701205496
21 2198891419230
22 8795774741170
23 35183603690432
24 140735633277488
25 562945474867230

List of values

[0, 2, 16, 88, 414, 1810, 7616, 31376, 127710, 516170, 2077552, 8341288, 33440190, 133941922, 536205056, 2145876128, 8586053694, 34350369050, 137416333936, 549701205496, 2198891419230, 8795774741170, 35183603690432, 140735633277488, 562945474867230]

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

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