A193511 a(n) = Sum of even divisors of Omega(n), a(1) = 0.
0, 0, 0, 2, 0, 2, 0, 0, 2, 2, 0, 0, 0, 2, 2, 6, 0, 0, 0, 0, 2, 2, 0, 6, 2, 2, 0, 0, 0, 0, 0, 0, 2, 2, 2, 6, 0, 2, 2, 6, 0, 0, 0, 0, 0, 2, 0, 0, 2, 0, 2, 0, 0, 6, 2, 6, 2, 2, 0, 6, 0, 2, 0, 8, 2, 0, 0, 0, 2, 0, 0, 0, 0, 2, 0, 0, 2, 0, 0, 0
Offset: 1
Keywords
Examples
a(16) = 6 because Omega(16) = 4 and the sum of the even divisors of 4 {2, 4} is 6.
Links
Programs
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Mathematica
Table[Total[Select[Divisors[PrimeOmega[n]], EvenQ[ # ]&]], {n, 58}] -
PARI
A146076(n) = if(n%2, 0, 2*sigma(n/2)); \\ This function from Michel Marcus, Apr 01 2015 A193511(n) = if(1==n,0,A146076(bigomega(n))); \\ Antti Karttunen, Jul 23 2017
Formula
From Antti Karttunen, Jul 23 2017: (Start)
(End)
Extensions
Description clarified by Antti Karttunen, Jul 23 2017
Comments