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 A224675 #10 Feb 17 2018 10:26:38 %S A224675 308,470,617,864,1166,1608,2230,3157,4554,6711,10083,15415,23907, %T A224675 37504,59351,94538,151300,242962,391084,630551,1017808,1644185, %U A224675 2657457,4296729,6948881,11239898,18182645,29415972,47591594,77000076,124583698 %N A224675 Number of (n+1) X 8 0..2 matrices with each 2 X 2 subblock idempotent. %C A224675 Column 7 of A224676. %H A224675 R. H. Hardin, <a href="/A224675/b224675.txt">Table of n, a(n) for n = 1..210</a> %F A224675 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 A224675 Empirical g.f.: x*(308 - 762*x + 277*x^2 + 438*x^3 - 291*x^4 + 15*x^5) / ((1 - x)^3*(1 - x - x^2)). - _Colin Barker_, Feb 17 2018 %e A224675 Some solutions for n=3: %e A224675 0 0 0 1 0 0 0 0 1 0 1 0 0 0 0 0 1 1 1 1 1 1 1 1 %e A224675 0 0 0 1 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 %e A224675 0 0 0 1 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 %e A224675 0 0 0 1 0 0 1 1 2 0 1 0 0 0 1 1 0 0 0 0 0 0 0 1 %K A224675 nonn %O A224675 1,1 %A A224675 _R. H. Hardin_, Apr 14 2013