OFFSET
1,3
COMMENTS
See A243865 for definition of twin divisor.
LINKS
Jens Kruse Andersen, Table of n, a(n) for n = 1..10000
EXAMPLE
The positive divisors of 40 are 1, 2, 4, 5, 8, 10, 20, 40. Of these, 2, 4, 8, 10, are twin divisors. So a(40) = the sum of these divisors, which is 24.
CROSSREFS
KEYWORD
nonn
AUTHOR
Juri-Stepan Gerasimov, Jun 16 2014
STATUS
approved