%I #3 Mar 30 2012 18:59:07
%S 1,1,3,3,5,7,11,19,35,69,151,339,829,2111,5607,15737,45289,136477,
%T 423279,1353671,4471673,15114479,52605755,187162155,681817179,
%U 2539492249,9646349779,37415172217,147745308403,594368656811
%N Diagonal sums of number triangle A107027.
%F a(n)=sum{k=0..floor(n/2), (n-2k-1)C((n-2k)*k, k)-(n-2k-2)*sum{j=0..k, C((n-2k)*k, j)}}
%K easy,nonn
%O 0,3
%A _Paul Barry_, May 09 2005