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 A207101 #9 Jun 19 2018 03:32:46 %S A207101 8,26,68,140,274,462,760,1158,1720,2431,3392,4550,6048,7825,10032, %T A207101 12597,15726,19285,23540,28343,33968,40250,47536,55575,64792,74916, %U A207101 86380,98890,112970,128216,145248,163636,184008,205905,230064,255892,284240,314483 %N A207101 Number of 0..n arrays x(0..3) of 4 elements with each no smaller than the sum of its two previous neighbors modulo (n+1). %C A207101 Row 4 of A207100. %H A207101 R. H. Hardin, <a href="/A207101/b207101.txt">Table of n, a(n) for n = 1..210</a> %F A207101 Empirical: a(n) = 3*a(n-2) + 2*a(n-3) - 3*a(n-4) - 6*a(n-5) + 6*a(n-7) + 3*a(n-8) - 2*a(n-9) - 3*a(n-10) + a(n-12). %F A207101 Empirical g.f.: x*(8 + 26*x + 44*x^2 + 46*x^3 + 42*x^4 + 32*x^5 + 18*x^6 + 4*x^7 - 2*x^8 - 3*x^9 + x^11) / ((1 - x)^5*(1 + x)^3*(1 + x + x^2)^2). - _Colin Barker_, Jun 19 2018 %e A207101 Some solutions for n=5: %e A207101 ..2....3....1....1....3....3....3....1....3....3....4....3....0....4....0....0 %e A207101 ..4....3....1....5....3....4....3....1....3....3....5....3....0....4....2....0 %e A207101 ..2....4....4....4....3....3....3....5....4....4....3....3....2....2....4....4 %e A207101 ..3....1....5....5....1....2....0....4....2....4....5....2....3....3....2....4 %Y A207101 Cf. A207100. %K A207101 nonn %O A207101 1,1 %A A207101 _R. H. Hardin_, Feb 15 2012