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Number of relations with 5 arguments on n nodes.
3

%I #13 Jul 02 2024 15:26:45

%S 2,2147516416,

%T 2355796086371179106111063334323891357095101187404796307182832141733986304

%N Number of relations with 5 arguments on n nodes.

%H Alois P. Heinz, <a href="/A051241/b051241.txt">Table of n, a(n) for n = 1..5</a>

%o (Python)

%o from itertools import product

%o from math import factorial, prod, lcm

%o from fractions import Fraction

%o from sympy.utilities.iterables import partitions

%o def A051241(n): return int(sum(Fraction(1<<sum(prod(r)//lcm(*r)*prod(p[d] for d in r) for r in product(p.keys(),repeat=5)),prod(q**p[q]*factorial(p[q]) for q in p)) for p in partitions(n))) # _Chai Wah Wu_, Jul 02 2024

%Y Cf. A000595, A000662, A001377.

%K nonn,bref

%O 1,1

%A _Vladeta Jovovic_