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A050781
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(n + sopf_n = m) and (m - sopf_m = n). Sequence gives values of m.
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2
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55, 72, 84, 119, 143, 256, 2106, 2211, 2279, 3024, 3150, 3551, 4284, 6360, 6500, 9350, 10200, 10285, 10919, 13560, 14279, 14351, 15606, 16463, 17063, 23595, 25011, 27208, 28208, 28600, 31460, 33096, 42180, 44330, 52320, 53053, 53824
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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COMMENTS
| sopf_m = sum of the prime factors of m (with multiplicity).
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EXAMPLE
| E.g. 585585 + (3+3+5+7+11+13+13) = 585640 - (2+2+2+5+11+11+11+11) = 585585.
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MATHEMATICA
| 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&)] (* From Harvey P. Dale, June 15 2011 *)
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CROSSREFS
| Cf. A050780, A050703-A050710.
Sequence in context: A068898 A068899 A053719 * A060260 A152080 A119224
Adjacent sequences: A050778 A050779 A050780 * A050782 A050783 A050784
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KEYWORD
| nonn,nice
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AUTHOR
| Patrick De Geest (pdg(AT)worldofnumbers.com), Sep 15 1999.
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