The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A193511 a(n) = Sum of even divisors of Omega(n), a(1) = 0. 3
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS Omega(n) = number of prime divisors of n counted with multiplicity : A001222 (also called bigomega(n)). a(1) = 0 by convention. LINKS Antti Karttunen, Table of n, a(n) for n = 1..10000 Index entries for sequences computed from exponents in factorization of n FORMULA From _Antti Karttunen_, Jul 23 2017: (Start) a(1) = 0, for n > 1, a(n) = A146076(A001222(n)). a(n) + A193512(n) = A290080(n). (End) EXAMPLE a(16) = 6 because Omega(16) = 4 and the sum of the even divisors of 4 {2, 4} is 6. MATHEMATICA Table[Total[Select[Divisors[PrimeOmega[n]], EvenQ[ # ]&]], {n, 58}] PROG (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 CROSSREFS Cf. A001222, A146076, A193510, A193512, A290080. Sequence in context: A216176 A359007 A128765 * A254218 A263147 A298100 Adjacent sequences: A193508 A193509 A193510 * A193512 A193513 A193514 KEYWORD nonn AUTHOR _Michel Lagneau_, Jul 29 2011 EXTENSIONS Description clarified by _Antti Karttunen_, Jul 23 2017 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified September 18 07:20 EDT 2024. Contains 375996 sequences. (Running on oeis4.)