OFFSET
1,2
FORMULA
a(A004023(n)) = 2. - Michel Marcus, Sep 09 2015
a(A046413(n)) = 4. - Bruno Berselli, Sep 09 2015
EXAMPLE
a(9) = 12 since the divisors of 111111111 are 1, 3, 9, 37, 111, 333, 333667, 1001001, 3003003, 12345679, 37037037, 111111111.
PROG
(PARI) a(n) = numdiv(10^n\9); \\ Michel Marcus, Sep 09 2015
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Henry Bottomley, May 02 2002
EXTENSIONS
Terms to a(280) in b-file from Hans Havermann, Aug 20 2011
a(281)-a(322) in b-file from Ray Chandler, Apr 22 2017
a(323)-a(352) ib b-file from Max Alekseyev, May 04 2022
STATUS
approved