A162763 - cp's OEIS frontend

A162763 Minimal total number of floors an elevator must travel to get n people waiting, respectively, at floors i = 1, 2, ..., n, to their destinations at floors n+1-i (= n, ..., 1), if the elevator can hold at most C = 3 people and starts at floor 1, and no passenger may get off the elevator before reaching his/her destination.

n	a(n)
1	0
2	2
3	4
4	6
5	8
6	10
7	12
8	18
9	22
10	27
11	31
12	35
13	39
14	47
15	53
16	60

[0, 2, 4, 6, 8, 10, 12, 18, 22, 27, 31, 35, 39, 47, 53, 60]