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A083002 Smallest oblong number having at least n distinct prime divisors. 3
2, 6, 30, 210, 4290, 43890, 510510, 53501910, 1487683470, 64790866140, 530514844860, 126408523110870, 3425113062060690, 660393717163700520, 26657280574571657010, 3448055881024876471350, 308480161111936386482910 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

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

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

LINKS

Table of n, a(n) for n=1..17.

EXAMPLE

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

PROG

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

CROSSREFS

Cf. A002378, A059958.

Sequence in context: A071290 A185693 A093449 * A192929 A077176 A101178

Adjacent sequences: A082999 A083000 A083001 * A083003 A083004 A083005

KEYWORD

nonn

AUTHOR

Jason Earls, May 30 2003

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

STATUS

approved

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Last modified February 4 04:29 EST 2023. Contains 360046 sequences. (Running on oeis4.)