1,1

The sum of the distinct primes dividing 2n. - Emeric Deutsch, Mar 11 2005

Table of n, a(n) for n=1..81.

a(6)=5 because 12 = 2^2*3 and 2+3 = 5.

with(numtheory): a:=proc(n) local b: b:=convert(factorset(2*n), list): add(b[j], j=1..nops(b)) end: seq(a(n), n=1..90); # Emeric Deutsch, Mar 11 2005

Sequence in context: A029648 A126103 A316895 * A029603 A204202 A025124

Adjacent sequences: A100027 A100028 A100029 * A100031 A100032 A100033

nonn,easy

N. J. A. Sloane, Nov 20 2004

More terms from Emeric Deutsch, Mar 11 2005

approved