A204822 Sum of divisors (A000203) of abundant numbers (A005101).

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

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: A179105 A376914 A096430 * A179166 A034964 A195897

Adjacent sequences: A204819 A204820 A204821 * A204823 A204824 A204825

Keyword

nonn

Author

Jaroslav Krizek, Jan 22 2012

Status

approved