OFFSET
1,2
EXAMPLE
Let d(n) be the number of divisors of n. Then a(2)!=2 because d(1+1)=d(1+2)=2. a(2)=3 because d(1+1)=2, d(1+3)=3, and d(3+3)=4 are all distinct.
CROSSREFS
KEYWORD
more,nonn
AUTHOR
Logan J. Kleinwaks, Oct 11 2017
STATUS
approved