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A052053 Digits of the prime factors of composite a(n) are not shared. 2

%I

%S 6,10,14,15,21,22,26,30,33,34,35,38,42,51,55,57,62,65,66,70,74,77,82,

%T 85,86,87,91,94,95,102,105,106,110,114,115,118,122,123,130,133,134,

%U 141,142,145,146,154,155,158,161,165,166,170,177,178,182,183,185,190,194

%N Digits of the prime factors of composite a(n) are not shared.

%H Nathaniel Johnston, <a href="/A052053/b052053.txt">Table of n, a(n) for n = 1..10000</a>

%e 141 = 3 * 47 is OK because the sets (3) and (4,7) share no digits. 39 = 3 * 13 is rejected because the sets (3) and (1,3) share the digit 3.

%p with(numtheory): isA052053 := proc(n) local d,dd,m,j,k: if(isprime(n) or not issqrfree(n))then return false: fi: d:=factorset(n): m:=nops(d): for k from 1 to m do dd[k]:=convert(convert(d[k],base,10),set): od: for j from 1 to m do for k from j+1 to m do if(not dd[j] intersect dd[k] = {})then return false: fi: od: od: return true: end: seq(`if`(isA052053(n), n, NULL), n=2..200); # _Nathaniel Johnston_, Jun 02 2011

%Y Cf. A052054.

%K nonn,easy,base

%O 1,1

%A _Patrick De Geest_, Dec 15 1999

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Last modified July 21 17:20 EDT 2019. Contains 325198 sequences. (Running on oeis4.)