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A249147 a(n) = 0 if A249148(n) = 1, otherwise the index of the least prime dividing A249148(n): a(n) = A055396(A249148(n)).

%I A249147 #8 Oct 25 2014 14:49:12
%S A249147 0,1,0,2,0,1,2,1,1,1,4,0,3,0,1,1,5,0,4,1,1,1,2,1,1,1,1,9,0,1,1,2,1,1,
%T A249147 1,11,0,2,6,1,1,12,0,1,1,2,1,1,14,0,5,2,2,1,15,0,1,4,4,1,1,1,3,2,1,1,
%U A249147 17,0,6,3,1,1,1,2,3,1,1,1,20,0,1,1,2,1,4,2,10,0,2,1,1,22,0,1,23,0,7
%N A249147 a(n) = 0 if A249148(n) = 1, otherwise the index of the least prime dividing A249148(n): a(n) = A055396(A249148(n)).
%H A249147 Antti Karttunen, <a href="/A249147/b249147.txt">Table of n, a(n) for n = 1..10000</a>
%F A249147 a(n) = A055396(A249148(n)).
%o A249147 (PARI)
%o A249147 A049084(n) = if(isprime(n), primepi(n), 0); \\ This function from _Charles R Greathouse IV_
%o A249147 A249147_write_bfile(up_to_n) = { my(pfcounts, n, a_n, x_n, f, k); pfcounts = vector(up_to_n); x_n = 1; for(n = 0, up_to_n, if((1 == x_n), pfcounts[1]++; x_n = pfcounts[1]; a_n = 0, f=factor(x_n); for(i=1,#f~,k = A049084(f[i,1])+1; pfcounts[k] += f[i,2]); a_n = A049084(f[1,1]); x_n = pfcounts[a_n+1]); if(n>0,write("b249147.txt", n, " ", a_n))); };
%o A249147 A249147_write_bfile(10000);
%o A249147 (Scheme) (define (A249147 n) (A055396 (A249148 n)))
%Y A249147 Cf. A049084, A055396, A249148.
%K A249147 nonn
%O A249147 1,4
%A A249147 _Antti Karttunen_, Oct 24 2014