A124940 - OEIS

A124940

Numbers n such that n and n+3 are 3-almost primes.

27, 42, 63, 75, 99, 102, 114, 171, 172, 242, 255, 258, 279, 282, 322, 354, 363, 366, 385, 399, 423, 425, 426, 435, 452, 474, 531, 575, 595, 602, 603, 606, 615, 639, 642, 651, 654, 665, 722, 759, 772, 830, 844, 894, 903, 906, 932, 935, 978

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OFFSET

1,1

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

EXAMPLE

27=3*3*3, 30=2*3*5; 42=2*3*7, 45=3*3*5.

PROG

(PARI) isok(n) = (bigomega(n) == 3) && (bigomega(n+3) == 3); \\ Michel Marcus, Oct 11 2013

CROSSREFS

Cf. A124941, A124942.

Sequence in context: A217008 A372443 A355903 * A272829 A306118 A114446

Adjacent sequences: A124937 A124938 A124939 * A124941 A124942 A124943

KEYWORD

nonn

AUTHOR

Zak Seidov, Nov 13 2006

STATUS

approved