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 A066709 #17 Nov 03 2023 17:59:36 %S A066709 1,0,1,1,2,1,0,2,4,1,1,5,8,5,1,0,3,14,15,6,1,1,9,25,32,21,7,1,0,4,32, %T A066709 62,56,28,8,1,1,14,56,109,122,84,36,9,1,0,5,60,170,242,210,120,45,10, %U A066709 1,1,20,105,275,436,457,330,165,55,11,1,0,6,100,375,732,912,792,495,220,66,12,1 %N A066709 Triangle T(r,c) of winning binary "same game" templates. %C A066709 T(r,c) is the number of winning templates with length r and minimum matching string length c; equivalently, ternary digits totaling r+c. For a definition and row sums 1,1,4,7,20, etc. see A066345. For antidiagonal sums 1,0,2,2,4,9, etc. see A066346. %H A066709 Sean A. Irvine, <a href="https://github.com/archmageirvine/joeis/blob/master/src/irvine/oeis/a066/A066709.java">Java program</a> (github) %F A066709 A035615(n) = 2 * Sum_{r=1..n-1, c=1..min(r,n-r)} T(r,c) * P(n-r,c) where P(n-r,c) = C(n-r-1,c-1) = (n-r-1)!/((n-r-c-2)!*(c-1)!). %e A066709 Rows: %e A066709 1; %e A066709 0,1; %e A066709 1,2,1; %e A066709 0,2,4,1; %e A066709 1,5,8,5,1; %e A066709 0,3,14,15,6,1; ... %e A066709 a(17) = T(6,2) = 3 winning templates with length 6 and total 8 = 6+2: 211211, 121121, 112112. %e A066709 A035615(6) = 2*( 1*1+0*1+1*3+1*1+2*2+1*1+1*1+0*1+2*1+1*1 ) = 2*13 = 26. %Y A066709 Cf. A035615, A066345, A066346, A007318. %K A066709 nonn,tabl %O A066709 1,5 %A A066709 _Frank Ellermann_, Dec 31 2001 %E A066709 More terms from _Sean A. Irvine_, Nov 03 2023