OFFSET
2,1
LINKS
G. C. Greubel, Table of n, a(n) for n = 2..10000
FORMULA
a(n) = n - 1 + A032742(n).
MAPLE
A032742 := proc(n) if n = 1 then 1; else max(op(numtheory[divisors](n) minus {n})) ; fi; end:
MATHEMATICA
f[n_]:=n+Divisors[n+1][[Length[Divisors[n+1]]-1]]; Table[f[n], {n, 2, 6!}] (* Vladimir Joseph Stephan Orlovsky, Mar 03 2010 *)
Table[n+Divisors[n][[-2]]-1, {n, 2, 80}] (* Harvey P. Dale, Jul 21 2015 *)
PROG
(PARI) a(n) = my(d = divisors(n)); n - 1 + d[#d-1]; \\ Michel Marcus, May 08 2016
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Juri-Stepan Gerasimov, Oct 10 2009
EXTENSIONS
Arbitrarily-defined a(1) removed by R. J. Mathar, Oct 21 2009
STATUS
approved