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 A200273 #8 May 20 2018 13:15:43 %S A200273 2,3,6,9,14,25,36,47,64,87,110,143,176,209,258,311,364,431,498,575, %T A200273 666,761,856,969,1092,1219,1364,1513,1662,1847,2032,2221,2432,2647, %U A200273 2876,3135,3394,3657,3946,4257,4568,4913,5258,5607,6004,6409,6814,7257,7700,8169 %N A200273 Number of 0..n arrays x(0..5) of 6 elements with zero 3rd differences. %C A200273 Row 4 of A200272. %H A200273 R. H. Hardin, <a href="/A200273/b200273.txt">Table of n, a(n) for n = 1..200</a> %F A200273 Empirical: a(n) = a(n-3) +a(n-5) +a(n-6) -a(n-8) -a(n-9) +a(n-10) -a(n-11) -a(n-13) +a(n-14) -a(n-15) -a(n-16) +a(n-18) +a(n-19) +a(n-21) -a(n-24). %F A200273 Empirical g.f.: x*(2 + 3*x + 6*x^2 + 7*x^3 + 11*x^4 + 17*x^5 + 22*x^6 + 24*x^7 + 26*x^8 + 33*x^9 + 31*x^10 + 32*x^11 + 26*x^12 + 26*x^13 + 21*x^14 + 15*x^15 + 10*x^16 + 8*x^17 + 6*x^18 + 3*x^19 + 3*x^20 + x^21 - x^23) / ((1 - x)^4*(1 + x)^2*(1 - x + x^2)*(1 + x + x^2)^2*(1 - x + x^2 - x^3 + x^4)*(1 + x + x^2 + x^3 + x^4)^2). - _Colin Barker_, May 20 2018 %e A200273 Some solutions for n=6: %e A200273 ..2....3....0....6....3....5....0....4....1....5....0....5....5....3....0....4 %e A200273 ..2....5....0....5....1....4....2....4....1....3....3....6....5....3....4....2 %e A200273 ..2....6....0....4....0....3....3....4....1....2....5....6....5....3....6....1 %e A200273 ..2....6....0....3....0....2....3....4....1....2....6....5....5....3....6....1 %e A200273 ..2....5....0....2....1....1....2....4....1....3....6....3....5....3....4....2 %e A200273 ..2....3....0....1....3....0....0....4....1....5....5....0....5....3....0....4 %Y A200273 Cf. A200272. %K A200273 nonn %O A200273 1,1 %A A200273 _R. H. Hardin_, Nov 15 2011