OFFSET
0,5
COMMENTS
Diagonal sums of number triangle A101124.
FORMULA
a(n)=sum{k=0..floor(n/2), if(k<n-k, T(n-2k, k), if(k=n-k, 1, 0))} where T(n, k)=(n/2)sum{j=0..floor(n/2), C(n-j, j)(-1)^j*(2k)^(n-2j)}.
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Dec 02 2004
STATUS
approved