login
This site is supported by donations to The OEIS 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) ). 0
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; internal format)
OFFSET

1,2

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: A116192 A090104 A075795 * A087851 A087852 A087853

Adjacent sequences:  A058265 A058266 A058267 * A058269 A058270 A058271

KEYWORD

nonn

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com), Dec 08 2000

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified February 14 09:18 EST 2012. Contains 205614 sequences.