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

Author

Jaroslav Krizek, Jan 22 2012

Keywords

• nonn

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000
• Eric Weisstein's World of Mathematics, Abundant Number

Crossrefs

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

Programs

Mathematica

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

PARI

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

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