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A036323 Composite numbers n such that digits of prime factors of n are either 7 or 8. 2

%I

%S 49,343,2401,5509,6139,6209,16807,38563,42973,43463,55139,62209,

%T 117649,269941,300811,304241,385973,435463,551509,552139,552209,

%U 615139,615209,619369,690199,698069,769129,777899,786769,823543,1889587,2105677

%N Composite numbers n such that digits of prime factors of n are either 7 or 8.

%C All terms are a product of at least two terms of A020470. - _David A. Corneth_, Oct 09 2020

%H David A. Corneth, <a href="/A036323/b036323.txt">Table of n, a(n) for n = 1..10000</a>

%H <a href="/index/Pri#prime_factors">Index entries for sequences related to prime factors</a>

%t Select[Range[25*10^5],CompositeQ[#]&&SubsetQ[{7,8},Flatten[ IntegerDigits/@ Transpose[ FactorInteger[#]][[1]]]]&] (* _Harvey P. Dale_, Jan 19 2015 *)

%Y Cf. A020470, A036302-A036325.

%K nonn,easy,base

%O 1,1

%A _Patrick De Geest_, Dec 15 1998

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Last modified March 2 09:45 EST 2021. Contains 341746 sequences. (Running on oeis4.)