A100005 Bisection of A001414.

0, 3, 5, 7, 6, 11, 13, 8, 17, 19, 10, 23, 10, 9, 29, 31, 14, 12, 37, 16, 41, 43, 11, 47, 14, 20, 53, 16, 22, 59, 61, 13, 18, 67, 26, 71, 73, 13, 18, 79, 12, 83, 22, 32, 89, 20, 34, 24, 97, 17, 101, 103, 15, 107, 109, 40, 113, 28, 19, 24, 22, 44, 15, 127, 46, 131, 26, 14, 137

Offset

1,2

Comments

Integer log of (2n-1): sum of primes dividing 2n-1 (with repetition). - Emeric Deutsch, Mar 10 2005

Links

Table of n, a(n) for n=1..69.

Example

a(23)=11 because 45=3^2*5^1 and 2*3+1*5=11.

Maple

with(numtheory): a:=proc(n) local b: b:=op(2, ifactors(n)): sum(b[j][1]*b[j][2], j=1..nops(b)): end: seq(a(2*n-1), n=1..78); # Emeric Deutsch, Mar 10 2005

Crossrefs

Sequence in context: A219781 A215107 A084393 * A215457 A130159 A127314

Adjacent sequences: A100002 A100003 A100004 * A100006 A100007 A100008

Keyword

nonn,easy

Author

N. J. A. Sloane, Nov 20 2004

Extensions

More terms from Emeric Deutsch, Mar 10 2005

Status

approved