%I #13 Dec 15 2017 17:36:01
%S 4,20,1278,1339,11074308238,19096347067
%N Sum of the primes from smallest prime factor of n to the largest prime factor of n = largest difference between consecutive divisors of n (ordered by size).
%C 10^11 < a(7) <= 8912510129422438. - _Giovanni Resta_, May 13 2016
%t Select[Range[2, 2000], (p = First /@ FactorInteger[#]; #-#/p[[1]] == Sum[ Prime[i], {i, PrimePi@ p[[1]], PrimePi@ p[[-1]]}]) &] (* _Giovanni Resta_, May 13 2016 *)
%o (PARI) isok(n) = {pf = factor(n)[,1]; my(pmin = vecmin(pf)); s = 0; forprime(p = pmin, vecmax(pf), s += p); s == n - n/pmin;} \\ _Michel Marcus_, Feb 03 2014
%Y Cf. A060681, A074036, A055233, A055514.
%K more,nonn
%O 1,1
%A _Jason Earls_, Sep 19 2002
%E a(5)-a(6) from _Giovanni Resta_, May 13 2016