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 A224547 #7 Aug 30 2018 15:03:16 %S A224547 80,137,193,294,428,635,943,1420,2162,3333,5193,8166,12936,20611, %T A224547 32983,52952,85210,137349,221653,357998,578544,935327,1512543,2446424, %U A224547 3957398,6402125,10357693,16757850,27113432,43869023,70980043,114846496 %N A224547 Number of (n+1) X 6 0..1 matrices with each 2 X 2 subblock idempotent. %C A224547 Column 5 of A224550. %H A224547 R. H. Hardin, <a href="/A224547/b224547.txt">Table of n, a(n) for n = 1..210</a> %F A224547 Empirical: a(n) = 4*a(n-1) - 5*a(n-2) + a(n-3) + 2*a(n-4) - a(n-5) for n>6. %F A224547 Empirical g.f.: x*(80 - 183*x + 45*x^2 + 127*x^3 - 80*x^4 + 6*x^5) / ((1 - x)^3*(1 - x - x^2)). - _Colin Barker_, Aug 30 2018 %e A224547 Some solutions for n=3: %e A224547 ..1..1..1..1..0..1....1..0..0..1..0..1....1..0..0..0..0..0....1..1..0..0..0..1 %e A224547 ..0..0..0..0..0..1....1..0..0..1..0..1....0..0..0..0..0..0....0..0..0..0..0..1 %e A224547 ..0..0..0..0..0..1....0..0..0..1..0..1....0..0..0..0..0..0....0..0..0..0..0..1 %e A224547 ..0..0..0..0..0..1....0..0..0..1..0..1....0..0..0..0..1..1....0..0..0..0..0..1 %Y A224547 Cf. A224550. %K A224547 nonn %O A224547 1,1 %A A224547 _R. H. Hardin_, Apr 10 2013