A129577 Triangle, read by rows, defined by T(n,k) = T(n-1,k) + T(n,k-1) for nk>0, where T(n,0) = T(n-1,0) + T(n-1,n-1) and T(n,n) = T(n,n-1) for n>0 with T(0,0)=1.

1, 1, 1, 2, 3, 3, 5, 8, 11, 11, 16, 24, 35, 46, 46, 62, 86, 121, 167, 213, 213, 275, 361, 482, 649, 862, 1075, 1075, 1350, 1711, 2193, 2842, 3704, 4779, 5854, 5854, 7204, 8915, 11108, 13950, 17654, 22433, 28287, 34141, 34141, 41345, 50260, 61368, 75318

Offset

0,4

Links

Table of n, a(n) for n=0..48.

Example

Triangle begins:
1;
1, 1;
2, 3, 3;
5, 8, 11, 11;
16, 24, 35, 46, 46;
62, 86, 121, 167, 213, 213;
275, 361, 482, 649, 862, 1075, 1075;
1350, 1711, 2193, 2842, 3704, 4779, 5854, 5854;
7204, 8915, 11108, 13950, 17654, 22433, 28287, 34141, 34141; ...

Prog

(PARI) T(n, k)=if(n<k || k<0, 0, if(n<=1, 1, if(n==k, T(n, k-1), if(k==0, T(n-1, 0)+T(n-1, n-1), T(n-1, k)+T(n, k-1)))))

Crossrefs

Cf. A129578 (column 0), A129579 (main diagonal), A129580 (row sums).

Sequence in context: A247309 A069831 A017820 * A320784 A107854 A118808

Adjacent sequences: A129574 A129575 A129576 * A129578 A129579 A129580

Keyword

nonn,tabl

Author

Paul D. Hanna, Apr 24 2007

Status

approved