OFFSET
1,1
FORMULA
For n > 2, a(n) = 4 * (n-2) * (2*n - 3) = A033586(n-2). - Max Alekseyev, May 04 2023
EXAMPLE
For n = 4 the graph is
.__.__.__.
|__|__|__|
Names of nodes:
1 2 3 4
a b c d
Maximal directed paths which start from node 3:
34dcba123c
34dc32ba12
34dc321ab2
34dc321abc
3cd432ba12
3cd4321ab2
3cd4321abc
3cba1234dc
321abc34dc
321abcd43c
There are also paths from nodes c,b,2. So a(4) = 4*10 = 40.
CROSSREFS
KEYWORD
nonn,walk
AUTHOR
Yasutoshi Kohmoto, Feb 18 2008
EXTENSIONS
Edited and extended by Max Alekseyev, May 04 2023
STATUS
approved