OFFSET
1,2
PROG
(PARI)
A026300(n, k)={ if(n<0 || k < 0, return(0) ; ) ; if(n<=1, 1, if(k==0, 1, sum(i=0, k/2, binomial(n, 2*i+n-k)*(binomial(2*i+n-k, i)-binomial(2*i+n-k, i-1))) ; ) ; ) ; }
{ vector(20, n, A026127(n)) } \\ R. J. Mathar, Dec 06 2006
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
Corrected by R. J. Mathar, Oct 26 2006
STATUS
approved