1,2

PARI programs from R. J. Mathar:

A026300(n, k)={ if(n<0 || k < 0, return(0) ; ) ; if(n<=1, 1, if(k==0, 1, if(k<n, A026300(n-1, k-2)+A026300(n-1, k-1)+A026300(n-1, k), A026300(n-1, n-2)+A026300(n-1, n-1)) ; ) ; ) ; }

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))) ; ) ; ) ; }

A026105(n, k)={ if(k==0 || n<=1, 1, A026300(n, k)-A026300(n-1, k-1) ; ) ; }

A026120(n, k)={ if(n<=1, if(k== -1 || k < n, 1, 0), A026105(n+1, k+1)-A026105(n, k) ; ) ; }

A026127(n)={ A026120(2*n-1, n-1) ; } { /* test for(i=0, 7, for(j=0, i, print(A026300(i, j))) ; print("; ") ; ) ; */ /* test for(i=-1, 7, for(j=-1, i, print(A026120(i, j))) ; print("; ") ; ) ; */ for(n=1, 20, print(n, " ", A026127(n))) ; }

Sequence in context: A061709 A135159 A020084 this_sequence A153295 A006770 A158827

Adjacent sequences: A026124 A026125 A026126 this_sequence A026128 A026129 A026130

nonn

Clark Kimberling (ck6(AT)evansville.edu)

Corrected by R. J. Mathar, Oct 26 2006