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 A212779 #6 Apr 20 2023 18:20:12 %S A212779 99,546,3010,16594,91482,504337,2780392,15328203,84503842,465866699, %T A212779 2568306672,14158984054,78057979457,430330886291,2372398990909, %U A212779 13078951921338,72103800421506,397505707375713,2191434937861300 %N A212779 Half the number of 0..5 arrays of length n+2 with second differences nonzero. %C A212779 Column 5 of A212782. %H A212779 R. H. Hardin, <a href="/A212779/b212779.txt">Table of n, a(n) for n = 1..210</a> %F A212779 Empirical: a(n) = 3*a(n-1) +12*a(n-2) +12*a(n-3) -6*a(n-4) -18*a(n-5) -14*a(n-6) -11*a(n-7) -16*a(n-8) -11*a(n-9) -a(n-10). %e A212779 Some solutions for n=5 %e A212779 ..3....0....4....3....1....1....3....1....4....1....4....3....4....0....3....3 %e A212779 ..0....1....0....4....0....0....4....4....0....3....0....4....1....3....4....0 %e A212779 ..2....5....3....1....1....1....4....3....5....4....5....1....2....3....4....0 %e A212779 ..3....0....3....5....3....5....1....3....5....1....3....5....0....5....5....2 %e A212779 ..3....1....5....2....3....5....3....1....0....1....3....5....4....4....5....0 %e A212779 ..5....5....2....5....5....0....2....5....2....0....5....2....5....2....0....5 %e A212779 ..2....1....0....2....5....2....5....2....0....2....0....0....4....2....3....0 %Y A212779 Cf. A212782. %K A212779 nonn %O A212779 1,1 %A A212779 _R. H. Hardin_, May 27 2012