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.

A229427 Number of nX7 0..2 arrays with horizontal differences mod 3 never 1, vertical differences mod 3 never -1, rows lexicographically nondecreasing, and columns lexicographically nonincreasing.

Table of values

n a(n)
1 30
2 282
3 2187
4 13345
5 66503
6 281016
7 1037193
8 3420692
9 10260128
10 28379127
11 73192023
12 177601008
13 408454945
14 895812869
15 1883191437
16 3811219431
17 7453126082
18 14128822736
19 26035706883
20 46749593643
21 81969420795
22 140605855270

List of values

[30, 282, 2187, 13345, 66503, 281016, 1037193, 3420692, 10260128, 28379127, 73192023, 177601008, 408454945, 895812869, 1883191437, 3811219431, 7453126082, 14128822736, 26035706883, 46749593643, 81969420795, 140605855270]

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

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