OFFSET
1,1
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..200
EXAMPLE
a(3)=10 since x=5^2*7*11*13*17*19*23*29=5391411025 is abundant with sigma(x)=10799308800 and sigma(x)-2*x=16486750.
MATHEMATICA
a[n_] := Module[{p = Prime[n]}, c = 1; pr = 1 + 1/p + 1/p^2; While[pr < 2, p = NextPrime[p]; pr *= (1 + 1/p); c++]; c + n - 1]; Array[a, 50] (* Amiram Eldar, Aug 14 2019 *)
CROSSREFS
KEYWORD
less,nonn
AUTHOR
Walter Kehowski, Mar 04 2007
EXTENSIONS
More terms from Stefan Steinerberger, May 11 2007
a(21) corrected and more terms added by Amiram Eldar, Aug 14 2019
STATUS
approved