A100006 Integer log of 2n: sum of primes dividing 2n (with repetition).

2, 4, 5, 6, 7, 7, 9, 8, 8, 9, 13, 9, 15, 11, 10, 10, 19, 10, 21, 11, 12, 15, 25, 11, 12, 17, 11, 13, 31, 12, 33, 12, 16, 21, 14, 12, 39, 23, 18, 13, 43, 14, 45, 17, 13, 27, 49, 13, 16, 14, 22, 19, 55, 13, 18, 15, 24, 33, 61, 14, 63, 35, 15, 14, 20, 18, 69, 23, 28, 16, 73, 14, 75

Offset: 1

Author

N. J. A. Sloane, Nov 20 2004

Keywords

• nonn
• easy

Examples

			a(20)=11 because 40=2^3*5^1 and 3*2+1*5=11.
		

Crossrefs

Bisection of A001414.

Programs

Maple

with(numtheory): a:=proc(n) local b: b:=op(2,ifactors(n)): add(b[j][1]*b[j][2],j=1..nops(b)): end: seq(a(2*n),n=1..88); # Emeric Deutsch, Mar 10 2005

Mathematica

Table[Plus @@ Times @@@ FactorInteger[2n], {n, 100}] (* Ray Chandler, Nov 12 2005 *)

Extensions

More terms from Emeric Deutsch, Mar 10 2005