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A374928
a(n) = binomial(n+1,2)!/(2*n-1)!!.
1
1, 2, 48, 34560, 1383782400, 4914953551872000, 2256176006302688870400000, 183516891399909333860213587968000000, 3471393410234796273065007947627034260275200000000, 19391842883498454572168038890844303744385142895096627200000000000
OFFSET
1,2
COMMENTS
a(n) is the construction number of the complete graph K_n.
REFERENCES
P. C. Kainen, R. Strong, and J. Tilley, Problem 12401, Amer. Math. Monthly, 130 (2023), 587.
LINKS
Eric Weisstein's World of Mathematics, Complete Graph.
Eric Weisstein's World of Mathematics, Construction Number.
MATHEMATICA
Table[Binomial[n + 1, 2]!/(2 n - 1)!!, {n, 10}]
PROG
(Python)
from sympy import factorial, factorial2
def A374928(n): return int(factorial(n*(n+1)>>1)//factorial2((n<<1)-1)) # Chai Wah Wu, Jul 24 2024
CROSSREFS
Sequence in context: A203311 A343694 A295177 * A098694 A137592 A203778
KEYWORD
nonn,easy
AUTHOR
Eric W. Weisstein, Jul 24 2024
STATUS
approved