
LINKS

Table of n, a(n) for n=1..20.
A. Catanzaro, J. Feldman, M. Higgins, B. Kimball, H. Kirk, A. C Maravelias, and D. Sinha, LCM Optimal Paths, Girls' Angle Bulletin, Vol. 13, No. 4 (2020), 1319.


EXAMPLE

For n = 3, the optimal path is 1, 2, 1, 3, which has cost 2 + 2 + 3 = 7.
For n = 4, the optimal path is 1, 3, 1, 2, 4, which has cost 3 + 3 + 2 + 4 = 12.
For n = 7, there are multiple optimal paths of which 1, 3, 6, 2, 4, 1, 5, 1, 7 is one and has cost 3 + 6 + 6 + 4 + 4 + 5 + 5 + 7 = 40.
For n = 20, an optimal path is 1, 11, 1, 13, 1, 17, 1, 19, 1, 7, 14, 2, 16, 8, 4, 12, 6, 18, 9, 3, 15, 5, 10, 20.
