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 A252529 #8 Dec 04 2018 11:04:04 %S A252529 778,706,1120,1592,4420,7136,10720,30752,49792,77696,227584,369152, %T A252529 589312,1746944,2836480,4585472,13680640,22224896,36167680,108265472, %U A252529 175931392,287277056,861405184,1399980032,2289958912,6872367104 %N A252529 Number of (n+2) X (5+2) 0..3 arrays with every 3 X 3 subblock row and diagonal sum equal to 0 2 3 6 or 7 and every 3 X 3 column and antidiagonal sum not equal to 0 2 3 6 or 7. %H A252529 R. H. Hardin, <a href="/A252529/b252529.txt">Table of n, a(n) for n = 1..210</a> %F A252529 Empirical: a(n) = 12*a(n-3) - 32*a(n-6) for n>8. %F A252529 Empirical g.f.: 2*x*(389 + 353*x + 560*x^2 - 3872*x^3 - 2026*x^4 - 3152*x^5 + 8256*x^6 + 152*x^7) / ((1 - 2*x)*(1 + 2*x + 4*x^2)*(1 - 4*x^3)). - _Colin Barker_, Dec 04 2018 %e A252529 Some solutions for n=4: %e A252529 ..3..1..3..3..1..3..3....2..0..0..2..0..0..2....1..0..1..1..0..1..1 %e A252529 ..2..2..3..2..2..3..2....1..0..1..1..0..1..1....1..1..0..1..1..0..1 %e A252529 ..3..2..2..3..2..2..3....1..1..0..1..1..0..1....3..0..0..3..0..0..2 %e A252529 ..3..1..3..3..0..3..3....2..0..0..3..0..0..2....1..0..1..1..0..1..1 %e A252529 ..2..2..3..2..2..3..2....1..0..1..1..0..1..2....1..1..0..1..1..0..1 %e A252529 ..3..2..2..3..2..2..3....1..1..0..1..1..0..1....2..0..0..3..0..0..3 %Y A252529 Column 5 of A252532. %K A252529 nonn %O A252529 1,1 %A A252529 _R. H. Hardin_, Dec 18 2014