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%I #14 Feb 17 2024 11:31:34
%S 0,2,22,130,1196,11698,107315,961924,8641491,78304633,714962670,
%T 6572968299
%N Number of terms of A066038 that do not exceed 10^n.
%C Luca & Moodley (2020) conjectured that a(n) ~ exp(gamma) * A006880(n).
%H Florian Luca and Damon Moodley, <a href="http://dx.doi.org/10.5817/AM2020-1-49">Composite positive integers whose sum of prime factors is prime</a>, Archivum Mathematicum, Vol. 56, No. 1 (2020), pp. 49-64.
%e There are 2 terms of A066038 not exceeding 10^1: 6 and 10. Thus a(1) = 2.
%t b[1] = 0; b[n_] := Plus @@ FactorInteger[n][[;; , 1]]; bQ[n_] := PrimeNu[n] > 1 && PrimeQ[b[n]]; p = 1; s = 0; seq = {}; Do[If[bQ[n], s++]; If[n == p, p *= 10; AppendTo[seq, s]], {n, 1, 10^6}]; seq
%Y Cf. A006880, A008472, A066038, A073004.
%K nonn,more
%O 0,2
%A _Amiram Eldar_, May 01 2020
%E a(11) from _Giovanni Resta_, May 05 2020
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