A110321 A Jacobsthal number related number triangle.

1, 1, 1, 6, 2, 1, 30, 18, 3, 1, 264, 120, 36, 4, 1, 2520, 1320, 300, 60, 5, 1, 30960, 15120, 3960, 600, 90, 6, 1, 428400, 216720, 52920, 9240, 1050, 126, 7, 1, 6894720, 3427200, 866880, 141120, 18480, 1680, 168, 8, 1, 123742080, 62052480, 15422400, 2600640

Offset

0,4

Comments

Row sums are A110322. Diagonal sums are A110323. Inverse is A110324.

Links

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

Formula

Number triangle T(n, k)=if(k<=n, n!*J(n-k+1)/k!), 0) where J(n)=A001045(n); Column k has e.g.f. (x^k/k!)/(1-x-2x^2);

Example

Rows begin
1;
1,1;
6,2,1;
30,18,3,1;
264,120,36,4,1;
2520,1320,300,60,5,1;
30960,15120,3960,600,6,1;

Crossrefs

Sequence in context: A289711 A101818 A138186 * A111553 A141473 A068931

Adjacent sequences: A110318 A110319 A110320 * A110322 A110323 A110324

Keyword

easy,nonn,tabl

Author

Paul Barry, Jul 20 2005

Status

approved