A100030 - OEIS

A100030

Bisection of A008472.

2, 2, 5, 2, 7, 5, 9, 2, 5, 7, 13, 5, 15, 9, 10, 2, 19, 5, 21, 7, 12, 13, 25, 5, 7, 15, 5, 9, 31, 10, 33, 2, 16, 19, 14, 5, 39, 21, 18, 7, 43, 12, 45, 13, 10, 25, 49, 5, 9, 7, 22, 15, 55, 5, 18, 9, 24, 31, 61, 10, 63, 33, 12, 2, 20, 16, 69, 19, 28, 14, 73, 5, 75, 39, 10, 21, 20, 18, 81, 7, 5

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OFFSET

1,1

COMMENTS

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

LINKS

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

EXAMPLE

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

MAPLE

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

CROSSREFS