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A225295 Pandigital numbers with exactly 4 prime factors (with multiplicity). 1

%I

%S 1023456987,1023458679,1023458967,1023465798,1023465897,1023465978,

%T 1023465987,1023467589,1023467859,1023468579,1023468597,1023468795,

%U 1023469758,1023478569,1023479586,1023479865,1023485967,1023486579,1023486957,1023487659,1023487965,1023489657,1023495678

%N Pandigital numbers with exactly 4 prime factors (with multiplicity).

%H Charles R Greathouse IV, <a href="/A225295/b225295.txt">Table of n, a(n) for n = 1..10000</a>

%F A014613 INTERSECTION A171102.

%F a(n) ~ 6n log n / (log log n)^3. - _Charles R Greathouse IV_, May 04 2013

%e a(1) = 1023456987 = 3^2 * 7 * 16245349.

%e a(2) = 1023458679 = 3^3 * 37905877.

%e a(3) = 1023458967 = 3^2 * 113 * 1006351.

%e a(4) = 1023465897 = 3^2 * 6379 * 17827.

%e a(5) = 1023465987 = 3^2 * 53 * 2145631.

%e a(511032) = 10123456987 = 7^2 * 9833 * 21011.

%o (PARI) is(n)=#vecsort(digits(n),,8)>9 && bigomega(n)==4 \\ _Charles R Greathouse IV_, May 04 2013

%Y Cf. A001358, A014613, A221646.

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

%Y Cf. A171102 (3-almost primes).

%K nonn,base,easy

%O 1,1

%A _Jonathan Vos Post_, May 04 2013

%E a(6)-a(23) from _Charles R Greathouse IV_, May 04 2013

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Last modified May 12 10:54 EDT 2021. Contains 343821 sequences. (Running on oeis4.)