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.
%I A180790 #5 Jun 02 2025 03:05:47
%S A180790 0,0,12,318,4868,53133,444019,2935676,16112283,75118525,307372602,
%T A180790 1118328968,3701885454,11222027568,31699803817,83633494240,
%U A180790 209004408969,494557127475,1121475446283,2431614016920,5096216430113,10285962253471
%N A180790 Number of distinct solutions of sum{i=1..8}(x(2i-1)*x(2i)) = 1 (mod n), with x() only in 1..n-1.
%C A180790 Column 8 of A180793
%H A180790 R. H. Hardin, <a href="/A180790/b180790.txt">Table of n, a(n) for n=1..183</a>
%e A180790 Solutions for sum of products of 8 1..2 pairs = 1 (mod 3) are
%e A180790 (1*1 + 1*1 + 1*1 + 1*1 + 1*1 + 1*1 + 1*2 + 1*2)
%e A180790 (1*1 + 1*1 + 1*1 + 1*1 + 1*1 + 1*2 + 1*2 + 2*2)
%e A180790 (1*1 + 1*1 + 1*1 + 1*1 + 1*2 + 1*2 + 2*2 + 2*2)
%e A180790 (1*1 + 1*1 + 1*1 + 1*2 + 1*2 + 1*2 + 1*2 + 1*2)
%e A180790 (1*1 + 1*1 + 1*1 + 1*2 + 1*2 + 2*2 + 2*2 + 2*2)
%e A180790 (1*1 + 1*1 + 1*2 + 1*2 + 1*2 + 1*2 + 1*2 + 2*2)
%e A180790 (1*1 + 1*1 + 1*2 + 1*2 + 2*2 + 2*2 + 2*2 + 2*2)
%e A180790 (1*1 + 1*2 + 1*2 + 1*2 + 1*2 + 1*2 + 2*2 + 2*2)
%e A180790 (1*1 + 1*2 + 1*2 + 2*2 + 2*2 + 2*2 + 2*2 + 2*2)
%e A180790 (1*2 + 1*2 + 1*2 + 1*2 + 1*2 + 1*2 + 1*2 + 1*2)
%e A180790 (1*2 + 1*2 + 1*2 + 1*2 + 1*2 + 2*2 + 2*2 + 2*2)
%e A180790 (1*2 + 1*2 + 2*2 + 2*2 + 2*2 + 2*2 + 2*2 + 2*2)
%K A180790 nonn
%O A180790 1,3
%A A180790 _R. H. Hardin_ Sep 20 2010