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%I #14 May 24 2023 12:34:16
%S 1,0,2,3,0,5,0,7,15,14,21,11,35,13,33,26,39,17,65,19,51,38,57,23,95,
%T 46,69,285,115,29,161,31,87,62,93,741,155,37,217,74,111,41,185,43,123,
%U 86,129,47,215,94,141,645,235,53,329,106,159,987,265,59,371,61,177,122
%N Smallest m such that sum of distinct primes dividing m equals n, or 0 if no such number exists (as at n=1,4,6).
%C a(n) = first occurrence of n in A008472 (sum of prime factors of n without repetition).
%C Note that for all primes p, p = a(p); if n is composite then a(n) must be a composite and the only zeros are 1, 4 and 6.
%H Alois P. Heinz, <a href="/A064502/b064502.txt">Table of n, a(n) for n = 0..20000</a> (terms n=1..1000 from Harry J. Smith)
%F a(n) = Min{x : A008472[x]=n}.
%e n = 217 = 3*17*197: sum = 3 + 17 + 197 = 217 = n.
%t t = Table[0, {100} ]; Do[a = Apply[Plus, Transpose[ FactorInteger[n]] [[1]]]; If[ a < 101 && t[[a]] == 0, t[[a]] = n], {n, 2, 10^5} ]; Append[t, 0]
%o (PARI) sopf(n)= { local(f,s=0); f=factor(n); for(i=1, matsize(f)[1], s+=f[i, 1]); return(s) } { for (n=1, 1000, if (n==1 || n==4 || n==6, m=0, if (isprime(n), m=n, m=1; while(sopf(m) != n, m++))); write("b064502.txt", n, " ", m) ) } \\ _Harry J. Smith_, Sep 16 2009
%Y Cf. A008472, A001414, A056240.
%K easy,nonn
%O 0,3
%A _Robert G. Wilson v_, Oct 05 2001
%E a(0)=1 prepended by _Alois P. Heinz_, May 24 2023
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