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 A132439 #19 Oct 05 2021 18:01:14 %S A132439 1,1,1,2,3,2,4,7,7,4,8,17,22,17,8,16,40,60,60,40,16,32,92,158,188,158, %T A132439 92,32,64,208,401,543,543,401,208,64,128,464,990,1498,1712,1498,990, %U A132439 464,128,256,1024,2392,3985,5079,5079,3985,2392,1024,256 %N A132439 Square array a(m,n) read by antidiagonals, where a(m,n) is the number of ways to move a chess queen from the lower left corner to square (m,n), with the queen moving only up, right, or diagonally up-right. %C A132439 a(m,n) is the sum of all the entries above it plus the sum of all the entries to the left of it plus the sum of all the entries on the northwest diagonal from it. %H A132439 Peter Kagey, <a href="/A132439/b132439.txt">Table of n, a(n) for n = 1..10011</a> (first 141 antidiagonals, flattened) %H A132439 Peter Kagey, <a href="/A132439/a132439.png">Parity bitmap of first 1024 rows and columns</a>. (Even and odd entries and represented by black and white pixels respectively.) %F A132439 a(1,1)=1; a(1,2)=1; a(1,3)=2; a(2,1)=1; a(2,2)=3; a(2,3)=7; a(3,1)=2; a(3,2)=7; a(3,3)=22; a(m,n) = 2*a(m-1,n)+2*a(m,n-1)-a(m-1,n-1)-3*a(m-2,n-1)-3*a(m-1,n-2)+4*a(m-2,n-2), where m >=3 or n >= 3 and a(m,n)=0 if m <= 0 or n <= 0. %F A132439 G.f.: (xy-x^2y-xy^2+x^3y^2+x^2y^3-x^3y^3)/(1-2x-2y+xy+3x^2y+3xy^2-4x^2y^2). %e A132439 The table begins %e A132439 1 1 2 4 8 16 32 ... %e A132439 1 3 7 17 40 92 208 ... %e A132439 2 7 22 60 158 401 990 ... %e A132439 4 17 60 188 543 1498 3985 ... %e A132439 8 40 158 543 1712 5079 14430 ... %e A132439 a(3,4)=4+17+2+7+22+1+7=60. %Y A132439 Cf. A035002. %K A132439 easy,nonn,tabl %O A132439 1,4 %A A132439 Martin J. Erickson (erickson(AT)truman.edu), Nov 13 2007