A075658 Numbers k such that the sum of prime divisors of k (A008472) is composite.

14, 15, 21, 26, 28, 30, 33, 35, 38, 39, 42, 45, 46, 51, 52, 55, 56, 57, 60, 62, 63, 65, 66, 69, 70, 74, 75, 76, 77, 78, 84, 85, 86, 87, 90, 91, 92, 93, 94, 95, 98, 99, 102, 104, 105, 106, 110, 111, 112, 114, 115, 117, 119, 120, 122, 123, 124, 126, 129, 130, 132, 133

Offset: 1

Author

Floor van Lamoen, Sep 23 2002 and Oct 02 2002

Keywords

• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A008472.

Programs

Magma

f:=func; [k:k in [2..150]| not IsPrime(f(k))]; // Marius A. Burtea, Nov 14 2019

Maple

A075658 := proc(n) local i,j,t1,t; t := NULL; for i from 2 to n do t1 := 0; for j from 1 to i do if i mod ithprime(j) = 0 then t1 := t1+ithprime(j); fi; od; if not(isprime(t1)) then t := t,i; fi; od; t; end;

Mathematica

Select[Range[133], CompositeQ[Plus @@ FactorInteger[#][[;;,1]]] &] (* Amiram Eldar, Nov 14 2019 *)

Extensions

Offset corrected by Amiram Eldar, Nov 14 2019