OFFSET
0,1
COMMENTS
It appears that the inequality a(n+1) > (2+2/n)*a(n) is true for n > 4.
FORMULA
For n>0, a(n) = A098475(n) - 1.
EXAMPLE
The values of the sigma_3 function (A001158) are increasing up to 25. Hence a(3)=24.
MATHEMATICA
Join[{4, 4}, Table[k=Floor[NSolve[Zeta[n](x-1)^n==x^n, x, WorkingPrecision->100][[ -1, 1, 2]]]; While[DivisorSigma[n, k]<DivisorSigma[n, k+1], k++ ]; k, {n, 2, 30}]]
CROSSREFS
KEYWORD
nonn
AUTHOR
T. D. Noe, Mar 23 2009
STATUS
approved