A117125 Positive integers that can be expressed as the difference between a factorial and a double factorial.

0, 1, 3, 4, 5, 9, 15, 16, 21, 22, 23, 72, 105, 112, 117, 118, 119, 336, 615, 672, 705, 712, 717, 718, 719, 1200, 4095, 4656, 4935, 4992, 5025, 5032, 5037, 5038, 5039

Offset: 1

Author

Paolo P. Lava and Giorgio Balzarotti, Apr 20 2006

Keywords

• nonn

Examples

			117 = 5! - 3!!
4992 = 7! - 6!!
		

Crossrefs

Cf. A110903, A111300.

Formula

n! - m!! being n! > m!!