OFFSET
1,2
COMMENTS
a(n) is the solution to the recurrence relation a(n) = a(a(n-3)) + a(n-a(n-3)), with the initial conditions: a(1) = 1, a(2) = 2, a(3) = a(4) = a(5) = a(6) = 3, a(7) = 4, a(8) = 5, a(9) = 6.
The sequence a(n) is monotonic, with successive terms increasing by 0 or 1. So the sequence hits every positive integer.
This sequence can be obtained from the Hofstadter-Conway sequence A004001 using a construction of Isgur et al.
LINKS
Nathan Fox, Table of n, a(n) for n = 1..10000
A. Isgur, R. Lech, S. Moore, S. Tanny, Y. Verberne, and Y. Zhang, Constructing New Families of Nested Recursions with Slow Solutions, SIAM J. Discrete Math., 30(2), 2016, 1128-1147. (20 pages); DOI:10.1137/15M1040505
MAPLE
CROSSREFS
KEYWORD
nonn
AUTHOR
Nathan Fox, Apr 25 2017
STATUS
approved