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 A200156 #8 May 17 2018 17:02:14 %S A200156 2,15,40,103,202,381,636,1033,1550,2287,3212,4451,5946,7869,10140, %T A200156 12969,16238,20211,24744,30147,36222,43349,51296,60493,70646,82267, %U A200156 95016,109467,125206,142897,162076,183477,206546,232123,259596,289879,322262 %N A200156 Number of 0..n arrays x(0..4) of 5 elements with zero 4th difference. %C A200156 Row 5 of A200154. %H A200156 R. H. Hardin, <a href="/A200156/b200156.txt">Table of n, a(n) for n = 1..200</a> %F A200156 Empirical: a(n) = a(n-1) +a(n-2) +a(n-4) -3*a(n-5) -a(n-6) +a(n-8) +3*a(n-9) -a(n-10) -a(n-12) -a(n-13) +a(n-14). %F A200156 Empirical g.f.: x*(2 + 13*x + 23*x^2 + 48*x^3 + 57*x^4 + 67*x^5 + 60*x^6 + 48*x^7 + 26*x^8 + 11*x^9 + x^10 - x^12 + x^13) / ((1 - x)^5*(1 + x)^3*(1 + x^2)^2*(1 + x + x^2)). - _Colin Barker_, May 17 2018 %e A200156 Some solutions for n=6: %e A200156 ..6....4....1....0....2....6....2....2....4....6....6....0....6....6....2....4 %e A200156 ..4....5....1....6....0....1....2....3....6....2....5....6....6....5....3....4 %e A200156 ..1....3....1....6....2....0....0....2....3....0....2....6....4....4....2....5 %e A200156 ..0....1....2....4....4....2....0....1....0....0....1....3....3....4....2....5 %e A200156 ..4....2....5....4....2....6....6....2....2....2....6....0....6....6....6....2 %Y A200156 Cf. A200154. %K A200156 nonn %O A200156 1,1 %A A200156 _R. H. Hardin_, Nov 13 2011