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 A144092 #4 Jun 02 2025 00:33:54 %S A144092 1,1,1,1,0,1,1,-1,1,1,1,0,2,0,1,1,1,2,-4,2,1,1,0,3,0,10,0,1,1,-1,3,9, %T A144092 15,-25,5,1,1,0,4,0,42,0,70,0,1,1,1,4,-16,56,196,196,-196,14,1,1,0,5, %U A144092 0,120,0,1176 %N A144092 Triangle of Hankel transforms of sequence array of C(n,floor(n/2)). %C A144092 The parity matrix A144093 of this array seems to have row sums A061338(n+1). %F A144092 Triangle (-1)^C(k+1,2)*H(n,k) where the k-th column of H(n,k) is the Hankel transform of the k-th column of the array [k<=n]*C(n-k,floor((n-k)/2). %e A144092 Triangle begins %e A144092 1, %e A144092 1, 1, %e A144092 1, 0, 1, %e A144092 1, -1, 1, 1, %e A144092 1, 0, 2, 0, 1, %e A144092 1, 1, 2, -4, 2, 1, %e A144092 1, 0, 3, 0, 10, 0, 1, %e A144092 1, -1, 3, 9, 15, -25, 5, 1, %e A144092 1, 0, 4, 0, 42, 0, 70, 0, 1, %e A144092 1, 1, 4, -16, 56, 196, 196, -196, 14, 1, %e A144092 1, 0, 5, 0, 120, 0, 1176, 0, 588, 0, 1 %K A144092 easy,sign,tabl %O A144092 0,13 %A A144092 _Paul Barry_, Sep 10 2008