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 A190095 #7 Jul 22 2025 12:01:39 %S A190095 6,26,66,130,212,312,412,527,650,782,914,1059,1204,1358,1520,1691, %T A190095 1862,2044,2226,2417,2608,2808,3008,3217,3430,3652,3874,4105,4336, %U A190095 4576,4816,5065,5314,5572,5830,6097,6364,6640,6916,7201,7486,7780,8074,8377,8680 %N A190095 Number of rhombuses on a (n+1)X7 grid. %C A190095 Column 6 of A190098 %H A190095 R. H. Hardin, <a href="/A190095/b190095.txt">Table of n, a(n) for n = 1..200</a> %F A190095 Empirical: a(n) = 2*a(n-1) -2*a(n-3) +a(n-4) for n>27 %e A190095 Some solutions for n=3 %e A190095 ..0..1....0..6....0..4....0..2....1..5....0..4....0..2....0..1....0..4....1..1 %e A190095 ..1..0....1..4....1..2....0..5....1..6....0..5....0..3....1..3....1..2....1..3 %e A190095 ..2..1....3..3....2..4....3..5....2..6....1..5....1..3....3..2....3..1....3..3 %e A190095 ..1..2....2..5....1..6....3..2....2..5....1..4....1..2....2..0....2..3....3..1 %K A190095 nonn %O A190095 1,1 %A A190095 _R. H. Hardin_ May 04 2011