OFFSET
1,2
COMMENTS
The sequence shows large jumps in value due to the sum occasionally forming a large prime, e.g., a(279) = 2650277753. The sequence is conjectured to be a permutation of the positive integers.
EXAMPLE
a(7) = 5 as Sum_{k=1..6} sigma(a(k)) = Sum_{k=1..6} A000203(a(k)) = 1 + 3 + 7 + 12 + 24 + 48 = 95, and 5 is the smallest unused number that shares a factor with 95.
CROSSREFS
KEYWORD
nonn
AUTHOR
Scott R. Shannon, Nov 02 2022
STATUS
approved