A014780 Triangle of numbers associated with Genocchi numbers.

1, 1, 1, 1, 3, 3, 5, 3, 3, 17, 17, 31, 25, 31, 17, 17, 155, 155, 293, 259, 349, 259, 293, 155, 155, 2073, 2073, 3991, 3681, 5151, 4289, 5151, 3681, 3991, 2073, 2073, 38227, 38227, 74381, 70235, 100325, 88507, 109765, 88507, 100325, 70235, 74381, 38227

Offset: 1

Author

N. J. A. Sloane

Keywords

• tabf
• nonn
• easy

Comments

When written in the triangle form as in the example below, the k-th entry (k>=1) in row n (n>=1) is the number of Dumont permutations of the first kind of length 2*n that start with k+1. - Alexander Burstein, May 14 2022

Examples

			Triangle begins:
   1;
   1,  1,  1;
   3,  3,  5,  3,  3;
  17, 17, 31, 25, 31, 17, 17;
  ...
		

Links

• G. Kreweras, Sur les permutations comptées par les nombres de Genocchi de 1-ière et 2-ième espèce, Europ. J. Comb., vol. 18, pp. 49-58, 1997.

Crossrefs

Cf. A110501, A014782, A014783, A014784.

Formula

Row sums give A110501.

Extensions

More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Mar 22 2003