OFFSET
1,3
COMMENTS
Also, the maximum detour index of any bipartite graph on n! nodes. - Andrew Howroyd, Dec 21 2017
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..100
Eric Weisstein's World of Mathematics, Transposition Graph
Eric Weisstein's World of Mathematics, Detour Index
FORMULA
a(n) = n!*(n!/2-1)^2 + (n!/2)^2*(n!-1) for n > 1. - Andrew Howroyd, Dec 20 2017
a(n) = A296819(n!). - Andrew Howroyd, Dec 23 2017
MATHEMATICA
Table[If[n == 1, 0, n! (n! (2 n! - 5) + 4)/4], {n, 20}]
PROG
(PARI) a(n) = if(n==1, 0, n!*(n!/2-1)^2 + (n!/2)^2*(n!-1)) \\ Andrew Howroyd, Dec 20 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Eric W. Weisstein, Dec 20 2017
EXTENSIONS
Terms a(5) and beyond from Andrew Howroyd, Dec 20 2017
STATUS
approved