OFFSET
1,3
FORMULA
a(n) ~ c * 10^n, where c = 0.0262215... is the asymptotic density of the coreful abundant numbers (see A308053). [Updated by Amiram Eldar, Sep 02 2022]
EXAMPLE
Below 10^2 there is only one coreful abundant number, 72, hence a(2) = 1.
MATHEMATICA
f[p_, e_] := (p^(e+1)-1)/(p-1)-1; csigma[1]=1; csigma[n_] := Times @@ (f @@@ FactorInteger[n]); cpQ[n_] := csigma[n] > 2*n; s={0}; c=0; p=100; Do[If[k==p, AppendTo[s, c]; p*=10]; If[cpQ[k], c++], {k, 1, 1000001}]; s
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Amiram Eldar, May 10 2019
EXTENSIONS
a(11) from Amiram Eldar, Sep 02 2022
STATUS
approved