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 A246732 #8 Nov 06 2018 08:19:55 %S A246732 124,260,548,1156,2436,5132,10812,22780,47996,101124,213060,448900, %T A246732 945796,1992716,4198492,8845884,18637564,39267844,82734180,174314244, %U A246732 367266052,773799948,1630334076,3434982396,7237230844,15248261636 %N A246732 Number of length n+4 0..3 arrays with no pair in any consecutive five terms totalling exactly 3. %H A246732 R. H. Hardin, <a href="/A246732/b246732.txt">Table of n, a(n) for n = 1..210</a> %F A246732 Empirical: a(n) = 2*a(n-1) + a(n-4). %F A246732 Empirical g.f.: 4*x*(31 + 3*x + 7*x^2 + 15*x^3) / (1 - 2*x - x^4). - _Colin Barker_, Nov 06 2018 %e A246732 Some solutions for n=4: %e A246732 ..2....3....0....1....0....1....2....1....0....1....3....1....2....3....1....0 %e A246732 ..3....1....1....1....2....0....3....1....2....1....3....3....3....1....1....0 %e A246732 ..2....1....0....3....2....0....3....1....2....1....3....1....3....3....3....0 %e A246732 ..2....3....0....1....2....0....3....1....2....1....1....3....3....3....3....0 %e A246732 ..2....3....1....3....0....1....3....1....0....1....3....1....3....3....3....2 %e A246732 ..2....3....1....3....0....0....2....1....2....3....1....1....3....3....3....0 %e A246732 ..2....1....1....3....2....0....3....1....2....1....3....1....1....3....1....2 %e A246732 ..0....1....1....3....2....0....2....0....2....3....1....3....1....1....1....2 %Y A246732 Column 3 of A246737. %K A246732 nonn %O A246732 1,1 %A A246732 _R. H. Hardin_, Sep 02 2014