A225295 Pandigital numbers with exactly 4 prime factors (with multiplicity).

1023456987, 1023458679, 1023458967, 1023465798, 1023465897, 1023465978, 1023465987, 1023467589, 1023467859, 1023468579, 1023468597, 1023468795, 1023469758, 1023478569, 1023479586, 1023479865, 1023485967, 1023486579, 1023486957, 1023487659, 1023487965, 1023489657, 1023495678

Offset: 1

Author

Jonathan Vos Post, May 04 2013

Keywords

• nonn
• base
• easy

Examples

			a(1) = 1023456987 = 3^2 * 7 * 16245349.
a(2) = 1023458679 = 3^3 * 37905877.
a(3) = 1023458967 = 3^2 * 113 * 1006351.
a(4) = 1023465897 = 3^2 * 6379 * 17827.
a(5) = 1023465987 = 3^2 * 53 * 2145631.
a(511032) = 10123456987 = 7^2 * 9833 * 21011.
		

Links

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

Crossrefs

Cf. A001358, A014613, A221646.

Cf. A050288 (pandigital primes), A175845 (pandigital numbers).

Cf. A171102 (3-almost primes).

Programs

PARI

is(n)=#vecsort(digits(n),,8)>9 && bigomega(n)==4 \\ Charles R Greathouse IV, May 04 2013

Formula

A014613 INTERSECTION A171102.

a(n) ~ 6n log n / (log log n)^3. - Charles R Greathouse IV, May 04 2013

Extensions

a(6)-a(23) from Charles R Greathouse IV, May 04 2013