A063068 Smallest number expressible as (a^2-1)(b^2-1) in at least n distinct ways [with b>=a>1].

9, 360, 2880, 241920, 588107520

Offset: 1

Author

Henry Bottomley, Jul 08 2001

Keywords

• more
• nonn

Comments

Note that each term is a multiple of the preceding term (at least up to a(5)).

Examples

			a(4)=241920 since 241920 =(4^2-1)(127^2-1) =(7^2-1)(71^2-1) =(9^2-1)(55^2-1) =(17^2-1)(29^2-1)
		

Links

• K. S. Brown, Numbers Expressible as (a^2-1)(b^2-1)
• K. S. Brown, MathPages Most Wanted List Problem #14

Crossrefs

Cf. A057535, A063066, A063067.