login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A204822 Sum of divisors (A000203) of abundant numbers (A005101). 4
28, 39, 42, 60, 72, 91, 90, 96, 124, 120, 120, 168, 144, 144, 195, 168, 186, 224, 180, 234, 252, 217, 216, 210, 280, 248, 240, 360, 312, 336, 288, 336, 403, 372, 392, 378, 363, 480, 360, 372, 546, 384, 508, 399, 468, 465, 504, 434, 576, 600, 504, 456, 504, 560 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Eric Weisstein's World of Mathematics, Abundant Number

FORMULA

a(n) = A000203(A005101(n)) = A005101(n) + A205098(n).

a(n) << n log log n with lim sup a(n)/(n log log n) approximately 7.192. - Charles R Greathouse IV, Feb 19 2013

MATHEMATICA

sdan[n_]:=Module[{ds=DivisorSigma[1, n]}, If[ds>2n, ds, 0]]; Select[ Array[ sdan, 300], #>0&] (* Harvey P. Dale, Aug 15 2015 *)

PROG

(PARI) for(n=6, 200, s=sigma(n); if(s>2*n, print1(s", "))) \\ Charles R Greathouse IV, Feb 19 2013

CROSSREFS

Cf. A204823 (sum of divisors of deficient numbers), A205098 (sum of proper divisors of abundant numbers).

Sequence in context: A080983 A179105 A096430 * A179166 A034964 A195897

Adjacent sequences:  A204819 A204820 A204821 * A204823 A204824 A204825

KEYWORD

nonn

AUTHOR

Jaroslav Krizek, Jan 22 2012

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 November 14 09:51 EST 2019. Contains 329111 sequences. (Running on oeis4.)