|
Search: id:A026302
|
|
|
| A026302 |
|
a(n) = number of (s(0), s(1), ..., s(n)) such that s(i) is a nonnegative integer and |s(i) - s(i-1)| <= 1 for i = 1,2,...,n, s(0) = 0, s(2n) = n. Also a(n) = T(2n,n), where T is the array in A026300. |
|
+0
1
|
|
| 1, 2, 9, 44, 230, 1242, 6853, 38376, 217242, 1239980, 7123765, 41141916, 238637282, 1389206210, 8112107475, 47495492400, 278722764954, 1638970147188, 9654874654438, 56965811111240, 336590781348276, 1991357644501170
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
PROGRAM
|
(PARI programs from R. J. Mathar) 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))) ; ) ; ) ; }
A026302(n)={ A026300(2*n, n) ; } { for(n=0, 21, print(n, " ", A026302(n))) ; }
|
|
CROSSREFS
|
Bisection of A026307.
Sequence in context: A163650 A013981 A162356 this_sequence A124889 A108308 A119855
Adjacent sequences: A026299 A026300 A026301 this_sequence A026303 A026304 A026305
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Clark Kimberling (ck6(AT)evansville.edu)
|
|
EXTENSIONS
|
Corrected by R. J. Mathar, Oct 26 2006
|
|
|
Search completed in 0.002 seconds
|
