A071962 Number of double points of the map that, for each term t of a sequence, counts the preceding terms that are greater than or equal to t.

1, 2, 4, 10, 26, 70, 216, 682, 2264, 7960, 29262, 113256, 452586, 1886306, 8109828, 36274448, 167157176

Offset: 0

Author

Zoran Sunic, Jun 24 2002

Keywords

• nonn
• more

Comments

It would be nice to have a formula or recurrence!

Examples

			The ten double points for n=3 form the following 5 pairs: (0000,0123), (0003,0120), (0020,0103), (0023,0100), (0021,0101)
		

Links

• Zoran Sunic, Young tableaux and other mutually describing sequences, Journal of Integer Sequences, Vol. 5 (2002), Article 02.1.5
• Zoran Sunic, Self-Describing Sequences and the Catalan Family Tree, Electronic Journal of Combinatorics, 10 (2003) #N5.

Extensions

More terms from John W. Layman, Jul 01 2002