A137582 Numbers having no inner zeros in decimal representation of their factorial.

0, 1, 2, 3, 4, 5, 6, 9, 10, 11, 14, 31, 40

Offset: 1

Author

Reinhard Zumkeller, Jan 27 2008

Keywords

• nonn
• base
• more

Comments

Conjecture: the sequence is finite.

Examples

			A000142(a(10)) = 11! = 399168*10^2;
A000142(a(11)) = 14! = 871782912*10^2;
A000142(a(12)) = 31! = 822283865417792281772556288*10^7.
		

Links

• Index entries for sequences related to factorial numbers.

Crossrefs

Cf. A000142, A027869, A027868, A137581.

Programs

PARI

isok(k) = my(f=k!); while(!(f % 10), f \= 10); #select(x->(x == 0), digits(f)) == 0; \\ Michel Marcus, Jun 28 2023

Formula

A137581(a(n)) = 0.