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 A188417 #6 Jul 22 2025 11:12:06 %S A188417 1,3,16,124,1308,17443,282349,5396178,119324602,3005520274, %T A188417 85152637884,2685936442822,93514176139534 %N A188417 Number of (2*n)Xn binary arrays with rows in nonincreasing order, 2 ones in every column and no more than 3 ones in any row. %C A188417 Row 2 of A188416 %e A188417 All solutions for 4X2 %e A188417 ..1..1....1..1....1..0 %e A188417 ..1..0....1..1....1..0 %e A188417 ..0..1....0..0....0..1 %e A188417 ..0..0....0..0....0..1 %K A188417 nonn %O A188417 1,2 %A A188417 _R. H. Hardin_ Mar 30 2011