OFFSET
1,2
COMMENTS
Conjecture: Numbers that are not in this sequence below any finite limit will never outnumber numbers that are.
That is, a(n) < 2n for all n. This holds for n < 10^10. - Charles R Greathouse IV, Apr 14 2014
The expected value of the first differences of this sequence is Sum_{q>=2} q*(p-1)/(2*lcm(2,...,q)) as q = p^k ranges over the prime powers, or approximately 1.39389022808623327303..., so the conjecture is very likely to be true. - Charlie Neder, Apr 26 2019
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
EXAMPLE
a(5) cannot be 5 because smallest number that is not a divisor of 4 is 3 and 3 is not a divisor of 5.
PROG
(PARI) step(n)=for(k=2, n+1, if(n%k, return((n\k+1)*k)))
v=vector(100); v[1]=1; for(n=2, #v, v[n]=step(v[n-1])); v \\ Charles R Greathouse IV, Apr 14 2014
CROSSREFS
KEYWORD
nonn,easy,changed
AUTHOR
J. Lowell, Apr 14 2014
EXTENSIONS
a(26)-a(63) from Charles R Greathouse IV, Apr 14 2014
STATUS
approved