A100029 Bisection of A008472.

0, 3, 5, 7, 3, 11, 13, 8, 17, 19, 10, 23, 5, 3, 29, 31, 14, 12, 37, 16, 41, 43, 8, 47, 7, 20, 53, 16, 22, 59, 61, 10, 18, 67, 26, 71, 73, 8, 18, 79, 3, 83, 22, 32, 89, 20, 34, 24, 97, 14, 101, 103, 15, 107, 109, 40, 113, 28, 16, 24, 11, 44, 5, 127, 46, 131, 26, 8, 137, 139, 50, 24

Offset

1,2

Comments

The sum of the distinct primes dividing 2n-1. - Emeric Deutsch, Mar 11 2005

Links

Table of n, a(n) for n=1..72.

Example

a(23)=8 because 45=3^2*5 and 3+5=8.

Maple

with(numtheory): a:=proc(n) local b: b:=convert(factorset(2*n-1), list): add(b[j], j=1..nops(b)) end: seq(a(n), n=1..80); # Emeric Deutsch, Mar 11 2005

Mathematica

Join[{0}, Total[Transpose[FactorInteger[#]][[1]]]&/@(2*Range[2, 80]-1)] (* Harvey P. Dale, Aug 05 2015 *)

Crossrefs

Sequence in context: A076565 A286517 A199423 * A099984 A130141 A130142

Adjacent sequences: A100026 A100027 A100028 * A100030 A100031 A100032

Keyword

nonn,easy

Author

N. J. A. Sloane, Nov 20 2004

Extensions

More terms from Emeric Deutsch, Mar 11 2005

Status

approved