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 A195220 #12 Oct 07 2019 03:05:18
%S A195220 1,1,7,1,19,91,1,37,1047,2277,1,61,5453,176471,111031,1,91,18903,
%T A195220 3395245,92031109,10654607,1,127,51205,31640829,9032683465,
%U A195220 149824887097,2021888119,1,169,117585,189677411,289301569283,103565705397639
%N A195220 T(n,k) is the number of lower triangles of an n X n integer array with each element differing from all of its diagonal, vertical, antidiagonal and horizontal neighbors by k or less and triangles differing by a constant counted only once.
%C A195220 Table starts
%C A195220 1 1 1 1 1
%C A195220 7 19 37 61 91
%C A195220 91 1047 5453 18903 51205
%C A195220 2277 176471 3395245 31640829 189677411
%C A195220 111031 92031109 9032683465 289301569283 4677360495205
%C A195220 10654607 149824887097 103565705397639 14572563308953245 774355028021195459
%C A195220 T(n,k) is the number of integer lattice points in kP where P is a (n*(n+1)/2-1)-dimensional polytope with vertices whose coordinates are all in {-1,0,1}. Therefore it is an Ehrhart polynomial in k, with degree n*(n+1)/2-1 and rational coefficients. - _Robert Israel_, Oct 06 2019
%H A195220 R. H. Hardin, <a href="/A195220/b195220.txt">Table of n, a(n) for n = 1..86</a>
%H A195220 Wikipedia, <a href="https://en.wikipedia.org/wiki/Ehrhart_polynomial">Ehrhart polynomial</a>
%F A195220 Empirical for rows:
%F A195220 T(1,k) = 1
%F A195220 T(2,k) = 3*k^2 + 3*k + 1
%F A195220 T(3,k) = (301/30)*k^5 + (301/12)*k^4 + (88/3)*k^3 + (227/12)*k^2 + (199/30)*k + 1
%F A195220 T(4,k) = (1207573/30240)*k^9 + (1207573/6720)*k^8 + (1000157/2520)*k^7 + (264247/480)*k^6 + (754417/1440)*k^5 + (338651/960)*k^4 + (2533393/15120)*k^3 + (90763/1680)*k^2 + (901/84)*k + 1
%F A195220 T(5,k) = (3508493543/18345600)*k^14 + (3508493543/2620800)*k^13 + (1116775769537/239500800)*k^12 + (422094048023/39916800)*k^11 + (377328209183/21772800)*k^10 + (78475421219/3628800)*k^9 + (1073748492569/50803200)*k^8 + (19848770813/1209600)*k^7 + (221251862417/21772800)*k^6 + (18121075223/3628800)*k^5 + (10435002133/5443200)*k^4 + (505904317/907200)*k^3 + (8793472607/75675600)*k^2 + (1397863/90090)*k + 1
%e A195220 Some solutions for n=6, k=5:
%e A195220 0 0 0 0
%e A195220 4 4 2 2 2 1 4 5
%e A195220 6 7 7 7 6 5 -3 -2 1 5 8 7
%e A195220 10 8 12 7 4 7 6 1 -6 -1 -4 -2 8 9 5 7
%e A195220 10 12 11 12 9 2 3 5 1 0 -1 -1 -1 -1 -2 5 5 8 9 8
%e A195220 7 7 8 12 9 5 1 3 5 2 4 5 -6 -3 0 0 1 -3 0 3 8 8 10 6
%Y A195220 Row 2 is A003215.
%K A195220 nonn,tabl
%O A195220 1,3
%A A195220 _R. H. Hardin_, Sep 13 2011