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A296785
Detour index for the n-transposition graph.
2
0, 1, 69, 6216, 846120, 185976720, 63980285040, 32772128296320, 23892198317930880, 23892346459702828800, 31800733054746203116800, 54951669873436196523801600, 120728819293576143371142220800, 331279880265073822312384445491200
OFFSET
1,3
COMMENTS
Also, the maximum detour index of any bipartite graph on n! nodes. - Andrew Howroyd, Dec 21 2017
LINKS
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
Sequence in context: A207985 A207197 A207217 * A363927 A364024 A264171
KEYWORD
nonn
AUTHOR
Eric W. Weisstein, Dec 20 2017
EXTENSIONS
Terms a(5) and beyond from Andrew Howroyd, Dec 20 2017
STATUS
approved