A083718 (greatest prime <= n) + (greatest prime factor of n).

2, 4, 6, 5, 10, 8, 14, 9, 10, 12, 22, 14, 26, 20, 18, 15, 34, 20, 38, 24, 26, 30, 46, 26, 28, 36, 26, 30, 58, 34, 62, 33, 42, 48, 38, 34, 74, 56, 50, 42, 82, 48, 86, 54, 48, 66, 94, 50, 54, 52, 64, 60, 106, 56, 64, 60, 72, 82, 118, 64, 122, 92, 68, 63, 74, 72, 134, 84, 90, 74

Offset: 1

Author

Reinhard Zumkeller, May 04 2003

Keywords

• nonn

Comments

a(n) = A007917(n) + A006530(n).

Crossrefs

Cf. A083714, A083715, A083716, A083717.

Programs

Mathematica

Join[{2},Table[If[PrimeQ[n],n,NextPrime[n,-1]]+FactorInteger[n][[-1,1]],{n,2,70}]] (* Harvey P. Dale, Aug 11 2016 *)