OFFSET
1,2
COMMENTS
See A093883 for a discussion and guide to related sequences.
FORMULA
a(n) ~ c * n^(n^2 - n - 2/3) / exp(3*n^2/2 - n*(n+1)*Pi/(2*sqrt(3)) - n), where c = Gamma(1/3) * 3^(1/12) * exp(Pi/(12*sqrt(3))) / (2^(4/3) * Pi^(4/3)) = 0.2945280196744096322469352538791946777977998766871923997662057483092872... - Vaclav Kotesovec, Nov 22 2023
MATHEMATICA
PROG
(Python)
from operator import mul
from functools import reduce
def v(n): return 1 if n==1 else reduce(mul, [j**2 - j*k + k**2 for k in range(2, n + 1) for j in range(1, k)])
print([v(n) for n in range(1, 11)]) # Indranil Ghosh, Jul 26 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Jan 04 2012
STATUS
approved