login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A058268 An approximation to sigma_{1/2}(n): ceiling( sum_{d|n} sqrt(d) ). 1
1, 3, 3, 5, 4, 7, 4, 8, 6, 8, 5, 13, 5, 9, 9, 12, 6, 14, 6, 15, 10, 11, 6, 20, 9, 12, 11, 17, 7, 22, 7, 17, 12, 13, 12, 26, 8, 13, 13, 24, 8, 25, 8, 20, 19, 14, 8, 31, 11, 20, 14, 21, 9, 27, 14, 27, 15, 16, 9, 40, 9, 16, 21, 25, 15, 29, 10, 23, 16, 29, 10, 42 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

MAPLE

with(numtheory); f := proc(n) local d, t1, t2; t2 := 0; t1 := divisors(n); for d in t1 do t2 := t2 + sqrt(d) end do; t2 end proc; # exact value of sigma_{1/2}(n)

CROSSREFS

Sequence in context: A090104 A333822 A075795 * A341729 A087851 A332932

Adjacent sequences:  A058265 A058266 A058267 * A058269 A058270 A058271

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Dec 08 2000

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 23 12:19 EDT 2021. Contains 346259 sequences. (Running on oeis4.)