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 A086328 #17 Feb 13 2018 12:58:17 %S A086328 1,2,2,8,2,28,2,96,62,284,2,1504,2,3560,2738,16896,2,67636,2,235736, %T A086328 109334,707480,2,4376848,206282,10408792,5417630,48753784,2,212560504, %U A086328 2,739236864,278770214,2333737292,133401818,13837799440,2 %N A086328 Number of n X n circulant singular (0,1) matrices over the reals. %C A086328 a(2*n+1) = A144926(2*n+1), n>0. a(2*p) = 2^p + binomial(2*p,p) if p is an odd prime, cf. A144926. - _Vladeta Jovovic_, Oct 02 2008 %H A086328 W. F. Lunnon, <a href="/A086328/b086328.txt">Table of n, a(n) for n = 1..39</a> %H A086328 W. F. Lunnon, <a href="/A144926/a144926.txt">C program for A144926 and A086328</a> %F A086328 a(n) = 2^n - A086323(n). %F A086328 For a prime p, a(p) = 2 and the two circulants are those with all rows equal (0, 0, 0, ..., 0) or all rows equal (1, 1, 1, ..., 1). %Y A086328 Cf. A086323, A086324. %K A086328 nonn %O A086328 1,2 %A A086328 Yuval Dekel (dekelyuval(AT)hotmail.com), Aug 30 2003 %E A086328 More terms from _Fred Lunnon_, Oct 28 2008 %E A086328 a(0) removed, a(1) corrected by _Max Alekseyev_, Sep 25 2009