OFFSET
1,2
COMMENTS
No prime number > 17 is in this sequence. - J. Lowell, Feb 06 2022
REFERENCES
S. Ramanujan, Collected Papers, Ed. G. H. Hardy et al., Cambridge 1927; Chelsea, NY, 1962, p. 87.
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
FORMULA
MATHEMATICA
(* This program is not suitable to compute a large number of terms. *) Reap[For[record = 0; n = 1, n <= 10^9, n = If[n < 60, n + 1, n + 60], tau = DivisorSigma[0, n]; If[tau > record, record = tau; t = DivisorSigma[0, tau]; Print[t]; Sow[t]]]][[2, 1]] (* Jean-François Alcover, Oct 08 2016 *)
CROSSREFS
KEYWORD
nonn,look
AUTHOR
N. J. A. Sloane, Jun 01 2014
STATUS
approved