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 A215339 #20 Jul 21 2017 10:09:28 %S A215339 0,0,0,2,0,5,0,2,3,7,0,5,0,9,8,10,0,14,0,17,10,2,0,13,5,15,12,23,0,20, %T A215339 0,26,25,19,12,2,0,21,3,5,0,33,0,2,32,2,0,21,7,42,20,41,0,23,27,3,41, %U A215339 2,0,34,0,33,61,26,44,27,0,53,26,31,0,34,0,2,68,21,29,18,0,5,39,43,0,71,39,2,3,10,0,83,46,2,65,49 %N A215339 a(n) = A001608(n) mod n. %C A215339 a(n) = 0 for n=1, n a prime, or n a Perrin pseudoprime (A013998). %H A215339 Seiichi Manyama, <a href="/A215339/b215339.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..1001 from Joerg Arndt) %o A215339 (PARI) %o A215339 M = [0, 1, 0; 0, 0, 1; 1, 1, 0]; %o A215339 a(n)=lift( trace( Mod(M,n)^n ) ); %o A215339 vector(66,n,a(n)) %Y A215339 Cf. A001608 (Perrin sequence), A013998 (Perrin pseudoprimes). %K A215339 nonn %O A215339 1,4 %A A215339 _Joerg Arndt_, Aug 16 2012