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.

A180780 Number of distinct solutions of sum{i=1..9}(x(2i-1)*x(2i)) = 0 (mod n), with x() only in 1..n-1.

Table of values

n a(n)
1 0
2 0
3 22
4 499
5 9730
6 136491
7 1430727
8 11783122
9 78770456
10 443607864
11 2151608155
12 9218591346
13 35373572400
14 123749340262
15 398005623516
16 1192411118090
17 3344070542568
18 8869510553867
19 22304900540593
20 53635016669434

List of values

[0, 0, 22, 499, 9730, 136491, 1430727, 11783122, 78770456, 443607864, 2151608155, 9218591346, 35373572400, 123749340262, 398005623516, 1192411118090, 3344070542568, 8869510553867, 22304900540593, 53635016669434]

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

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