A083002 Smallest oblong number having at least n distinct prime divisors.

2, 6, 30, 210, 4290, 43890, 510510, 53501910, 1487683470, 64790866140, 530514844860, 126408523110870, 3425113062060690, 660393717163700520, 26657280574571657010, 3448055881024876471350, 308480161111936386482910

Offset: 1

Author

Jason Earls, May 30 2003

Keywords

• nonn

Comments

a(18) <= 32521466098360753728404190. - Donovan Johnson, Oct 05 2011

Oblong numbers are those of the form n(n+1) = A002378(n) = 2*A000217(n).

Examples

			a(4)= 210 = 2*3*5*7.
		

Crossrefs

Cf. A002378, A059958.

Programs

PARI

{odf(m) = print1(0","); for(n=1,m, k=1; while(omega(k*(k+1))!=n,k++); print1(k*(k+1)",")) }

Extensions

More terms from Don Reble, Jun 03 2003

a(15)-a(16) from Donovan Johnson, Apr 26 2009

a(17) from Donovan Johnson, Sep 15 2010