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 A145973 #11 Jun 05 2021 17:09:17 %S A145973 1,0,1,2,0,1,0,4,0,1,7,0,6,0,1,0,18,0,8,0,1,29,0,33,0,10,0,1,0,86,0, %T A145973 52,0,12,0,1,131,0,179,0,75,0,14,0,1,0,427,0,316,0,102,0,16,0,1,625,0, %U A145973 972,0,505,0,133,0,18,0,1 %N A145973 Triangle read by rows, square of A053121. %C A145973 Left border = aerated version of A007852. %F A145973 Triangle read by rows, A053121^2. %e A145973 First few rows of the triangle: %e A145973 1; %e A145973 0, 1; %e A145973 2, 0, 1; %e A145973 0, 4, 0, 1; %e A145973 7, 0, 6, 0, 1; %e A145973 0, 18, 0, 8, 0, 1; %e A145973 29, 0, 33, 0, 10, 0, 1; %e A145973 0, 86, 0, 52, 0, 12, 0, 1; %e A145973 131, 0, 179, 0, 75, 0, 14, 0, 1; %e A145973 0, 427, 0, 316, 0, 102, 0, 16, 0, 1; %e A145973 625, 0, 972, 0, 505, 0, 133, 0, 18, 0, 1; %e A145973 ... %p A145973 A145973 := proc(n,k) %p A145973 add(A053121(n,j)*A053121(j,k),j=k..n) ; %p A145973 end proc: # _R. J. Mathar_, Mar 03 2013 %Y A145973 Cf. A053121. %Y A145973 Cf. A007852, A145974 (row sums). %Y A145973 This triangle is the square of A053121. %K A145973 nonn,tabl %O A145973 0,4 %A A145973 _Gary W. Adamson_ and _Roger L. Bagula_, Oct 25 2008