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 A115520 #4 Mar 30 2012 17:38:16 %S A115520 1,2,5,12,23,36,61,88,123,170,227,288,373,462,565,688,827,972,1153, %T A115520 1340,1547,1782,2039,2304,2617,2938,3285,3668,4079,4500,4981,5472, %U A115520 5995,6562,7163,7776,8461,9158,9893,10680,11507,12348,13273,14212,15195,16238,17327,18432,19633 %N A115520 Number of ordered triples (i,j,k) in range [0..n] satisfying i == j mod 2 and j == k mod 3. %F A115520 a(n) = binomial(n+1,3) - linear (PORC) correction term which depends on n mod 6. %Y A115520 Cf. A115523. %K A115520 nonn %O A115520 0,2 %A A115520 _N. J. A. Sloane_ and _Vinay Vaishampayan_, Mar 09 2006