%N Sum of base and exponent of prime powers.
%C If n = p^q, where p is prime and q > 0, then p+q is in the sequence.
%C If n is not of that form, omit the term.
%C Might be a good "puzzle" sequence - guess the rule given the first ten or so terms.
%e n = 3 = 3^1, so 3+1 = 4 is a term; n = 4 = 2^2, so 2+2 = 4 is again a term; n = 5 = 5^1, so we get 5+1 =6.
%e But 6 is not a prime power, so we skip it.
%o (PARI) for(n=1,300,fac=factor(n);if(matsize(fac)==1,print1(fac[1,1]+fac[1,2],",")))
%Y Cf. A112375, A064438.
%Y A008474 is another version, defined for all n.
%A _Zak Seidov_, Dec 04 2005
%E Edited and extended by _Klaus Brockhaus_, Jan 21 2006
%E Further edited by _N. J. A. Sloane_, Nov 19 2018