cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A050704 Composite numbers k with the property that k minus the sum of the prime factors of k is prime.

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%I A050704 #21 Dec 19 2021 16:17:55
%S A050704 8,9,10,12,14,15,20,21,26,28,33,35,38,39,40,44,48,51,54,56,62,65,68,
%T A050704 69,76,77,80,86,88,91,93,95,96,111,112,116,122,123,124,129,133,136,
%U A050704 146,148,152,159,161,176,188,189,198,201,203,206,209,210,213,215,217,218
%N A050704 Composite numbers k with the property that k minus the sum of the prime factors of k is prime.
%C A050704 Prime factors are totaled with multiplicity, e.g., 8 = 2*2*2 so the sum of the prime factors of 8 is 6. - _Harvey P. Dale_, Jun 14 2011
%H A050704 Amiram Eldar, <a href="/A050704/b050704.txt">Table of n, a(n) for n = 1..10000</a>
%e A050704 E.g., 161 = 7*23; 161 - (7 + 23) = 161 - 30 = 131, which is prime.
%t A050704  Select[Range[250],CompositeQ[#]&&PrimeQ[#-Total[Times@@@ FactorInteger[ #]]]&] (* _Harvey P. Dale_, Jun 14 2011 *)
%Y A050704 Cf. A050703-A050710.
%K A050704 nonn,nice
%O A050704 1,1
%A A050704 _Patrick De Geest_, Aug 15 1999