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A241049 Smallest number k such that sopf(k)/digsum(k) = prime(n) where sopf(k) is the sum of the distinct primes dividing k and digsum(k) the sum of digits of k. 1

%I #6 Apr 16 2014 17:26:36

%S 42,104,130,10,212,1336,1630,1003,1556,3122,2455,5298,9105,13842,3241,

%T 5230,10020,8754,11671,10104,16305,13141,7628,12786,16201,2012,18007,

%U 10630,11965,12607,13945,14623,38234,24343,30823,24020,7846,17905,11348,12061,27517

%N Smallest number k such that sopf(k)/digsum(k) = prime(n) where sopf(k) is the sum of the distinct primes dividing k and digsum(k) the sum of digits of k.

%C a(n) is the smallest k such that A008472(k)/ A007953(k) = prime(n).

%H Michel Lagneau, <a href="/A241049/b241049.txt">Table of n, a(n) for n = 1..200</a>

%e a(7) = 1630 because A008472(1630)/ A007953(1630) = 170/10 = 17 = prime(7).

%t lst={};Do[k=1;While[Plus @@ First[ Transpose[ FactorInteger[k]]]/

%t Plus@@IntegerDigits[k]!=Prime[n],k++];AppendTo[lst,k],{n,1,42}];lst

%Y Cf. A008472, A007953.

%K nonn,base

%O 1,1

%A _Michel Lagneau_, Apr 15 2014

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