OFFSET
1,2
COMMENTS
This sequence is a subsequence of A020492. There is no further term up to 33*10^6. Is it true that 10 divides all multi-digit terms of the sequence?
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..36 (calculated using data from Jud McCranie)
EXAMPLE
sigma(237000) = phi(237000)*(2+3+7+0+0+0).
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Farideh Firoozbakht, May 15 2008
EXTENSIONS
7 more terms Sean A. Irvine, Sep 23 2009
a(20)-a(25) from Donovan Johnson, Mar 06 2012
a(26) from Amiram Eldar, Dec 04 2019, using data from Jud McCranie
STATUS
approved