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%I #21 Dec 25 2016 21:27:34
%S 55,72,84,119,143,256,2106,2211,2279,3024,3150,3551,4284,6360,6500,
%T 9350,10200,10285,10919,13560,14279,14351,15606,16463,17063,23595,
%U 25011,27208,28208,28600,31460,33096,42180,44330,52320,53053,53824
%N Numbers k such that sopfr(k) = sopfr(k - sopfr(k)).
%C sopfr(k) = sum of the prime factors of k (with multiplicity).
%H Paolo P. Lava, <a href="/A050781/b050781.txt">Table of n, a(n) for n = 0..200</a>
%e sopfr(72) = 2+2+2+3+3 = 12 = 2+2+3+5 = sopfr(72 - sopfr(72)), so 72 is in the sequence.
%t sopf[n_]:=Module[{sopfn=Total[Times@@@FactorInteger[n]],m},m=n+sopfn;If[n==m-Total[Times@@@FactorInteger[m]],m,0]]; DeleteCases[Table[ sopf[n],{n,55000}],_?(#==0&)] (* _Harvey P. Dale_, Jun 15 2011 *)
%Y Cf. A001414, A050703-A050710, A050780.
%K nonn,nice
%O 0,1
%A _Patrick De Geest_, Sep 15 1999
%E Edited by _Jon E. Schoenfield_, Dec 25 2016
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