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 A187464 #6 Jul 22 2025 10:46:38 %S A187464 144,89618,5098224,100936174,1061948616,7706500654,41131010240, %T A187464 180898687166,670434819776,2192125079476,6398465414348,17262285779402 %N A187464 Number of 4X4 0..n arrays with all the 2X2 subblocks nonsingular and the array of 2X2 subblock determinants symmetric. %C A187464 Row 3 of A187462 %K A187464 nonn %O A187464 1,1 %A A187464 _R. H. Hardin_ Mar 10 2011