A291466 First of the smallest n consecutive sphenic numbers A007304.

30, 230, 1309

Offset: 1

Author

Jonathan Sondow, Oct 17 2017

Keywords

• nonn
• fini
• full

Comments

Every 4th consecutive number is divisible by 4 = 2*2 and therefore is not sphenic, so a(n) does not exist for n >= 4.

Examples

			30 = 2*3*5 is the first spheric number, so a(1) = 30.
The first case of two consecutive sphenic numbers is 230 = 2*5*23 and 231 = 3*7*11, so a(2) = 230.
The first case of three is 1309 = 7*11*17, 1310 = 2*5*131, and 1311 = 3*19*23, so a(3) = 1309.
		

Links

• Wikipedia, Sphenic number

Crossrefs

Cf. A007304.