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.

A280956 Number of nX3 0..2 arrays with no element equal to more than one of its horizontal, vertical and antidiagonal neighbors and with new values introduced in order 0 sequentially upwards.

Table of values

n a(n)
1 4
2 42
3 241
4 1554
5 9899
6 63085
7 402077
8 2562733
9 16334111
10 104108376
11 663554669
12 4229292041
13 26956196587
14 171810442122
15 1095066516245
16 6979614612419
17 44485900541127
18 283539343806484
19 1807191908208865
20 11518481171610485

List of values

[4, 42, 241, 1554, 9899, 63085, 402077, 2562733, 16334111, 104108376, 663554669, 4229292041, 26956196587, 171810442122, 1095066516245, 6979614612419, 44485900541127, 283539343806484, 1807191908208865, 11518481171610485]

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

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