OFFSET
1,1
COMMENTS
a(1) = 2, a(2) = 3 and a(i) is the next smallest number greater than a(i-1) such that a(i) - a(j) is not a(1) or a(m) or a(m) - a(n) with 1 <= j < i, 1 <= n < m < i. - Ben Paul Thurston, Feb 18 2019
FORMULA
a(n) = A004979(n + 1) - 1. - Sean A. Irvine, Jun 05 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved