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 A229007 #8 Sep 13 2013 20:11:56 %S A229007 4,14,46,130,332,830,2054,5108,12790,32146,80942,203898,513498, %T A229007 1292934,3254868,8193210,20623908,51914372,130680214,328953874, %U A229007 828059138,2084434524,5247046924,13208134738,33248182980,83693989466,210678694852 %N A229007 Number of arrays of median of three adjacent elements of some length n+2 0..3 array, with no adjacent equal elements in the latter. %C A229007 Column 3 of A229012. %H A229007 R. H. Hardin, <a href="/A229007/b229007.txt">Table of n, a(n) for n = 1..210</a> %F A229007 Empirical: a(n) = 3*a(n-1) -5*a(n-3) +2*a(n-4) +11*a(n-5) -11*a(n-6) -2*a(n-7) +19*a(n-8) -8*a(n-9) -13*a(n-10) +28*a(n-11) -18*a(n-12) +a(n-13) +26*a(n-14) -24*a(n-15) +9*a(n-16) +15*a(n-17) -21*a(n-18) +13*a(n-19) +5*a(n-20) -12*a(n-21) +19*a(n-22) -9*a(n-23) -a(n-24) +4*a(n-25) -4*a(n-26) +2*a(n-27). %e A229007 Some solutions for n=4 %e A229007 ..2....2....2....1....3....3....1....2....2....3....2....1....2....2....2....1 %e A229007 ..0....2....2....2....1....2....2....3....2....2....3....0....2....2....2....3 %e A229007 ..1....1....3....0....2....2....3....2....2....1....1....3....1....1....0....0 %e A229007 ..1....3....0....3....1....2....2....2....1....1....2....0....2....1....3....1 %K A229007 nonn %O A229007 1,1 %A A229007 _R. H. Hardin_, Sep 10 2013