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 A214875 #29 Jan 22 2020 21:06:33
%S A214875 1,1,6,72,1289,29889,831174,26455564,934766625,35896627737,
%T A214875 1475461220832,64175536953702,2928055871469177,139180794974903769,
%U A214875 6854741942660442918,348244986517582367748,18183302860592129336633,972820066413029570529513,53192593416458179801289034
%N A214875 Number of 4 X n nonconsecutive tableaux.
%C A214875 A standard Young tableau (SYT) where entries i and i+1 never appear in the same row is called a nonconsecutive tableau.
%H A214875 Alois P. Heinz, <a href="/A214875/b214875.txt">Table of n, a(n) for n = 0..534</a>
%H A214875 T. Y. Chow, H. Eriksson and C. K. Fan, <a href="https://doi.org/10.37236/1895">Chess tableaux</a>, Elect. J. Combin., 11 (2) (2005), #A3.
%H A214875 S. Dulucq and O. Guibert, <a href="https://doi.org/10.1016/S0012-365X(96)83009-3">Stack words, standard tableaux and Baxter permutations</a>, Disc. Math. 157 (1996), 91-106.
%H A214875 Wikipedia, <a href="https://en.wikipedia.org/wiki/Young_tableau">Young tableau</a>
%F A214875 a(n) ~ 3^(4*n+12) / (2^13 * Pi^(3/2) * n^(15/2)). - _Vaclav Kotesovec_, Jul 16 2014
%e A214875 a(2) = 6:
%e A214875 [1, 5] [1, 4] [1, 3] [1, 4] [1, 3] [1, 3]
%e A214875 [2, 6] [2, 6] [2, 6] [2, 5] [2, 5] [2, 4]
%e A214875 [3, 7] [3, 7] [4, 7] [3, 7] [4, 7] [5, 7]
%e A214875 [4, 8] [5, 8] [5, 8] [6, 8] [6, 8] [6, 8].
%p A214875 a:= proc(n) option remember; `if`(n<3, [1,1,6][n+1], ((1620*n^7
%p A214875 -13770*n^6 +41958*n^5 -48762*n^4 -6642*n^3 +62532*n^2 -48600*n
%p A214875 +11664)*a(n-3) +(-3260*n^7 +11360*n^6 -4169*n^5 -19015*n^4
%p A214875 +14521*n^3 +6179*n^2 -7380*n +1764)*a(n-2) +(-80*n +1964*n^3
%p A214875 -7469*n^4 +3631*n^2 -5236*n^5 +2590*n^6 +1660*n^7 -300)*a(n-1))
%p A214875 /((2*n+3)*(n+3)*(10*n^2-15*n-1)*(n+2)^3))
%p A214875 end:
%p A214875 seq(a(n), n=0..25);
%t A214875 a[0] = a[1] = 1; a[2] = 6; a[n_] := a[n] = ((1620n^7 - 13770n^6 + 41958n^5 - 48762n^4 - 6642n^3 + 62532n^2 - 48600n + 11664) a[n-3] + (-3260n^7 + 11360n^6 - 4169n^5 - 19015n^4 + 14521n^3 + 6179n^2 - 7380n + 1764) a[n-2] + (-80n + 1964n^3 - 7469n^4 + 3631n^2 - 5236n^5 + 2590n^6 + 1660n^7 - 300) a[n-1])/((2n + 3)(n + 3)(10n^2 - 15n - 1)(n + 2)^3);
%t A214875 Table[a[n], {n, 0, 25}] (* _Jean-François Alcover_, Jun 01 2018, from Maple *)
%Y A214875 Row n=4 of A214021.
%K A214875 nonn
%O A214875 0,3
%A A214875 _Alois P. Heinz_, Jul 28 2012