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 A280420 Product of divisors of n!. 2
 1, 1, 2, 36, 331776, 42998169600000000, 7244150201408990671659859968000000000000000, 1182813011613388022005884215741990164001544397058025540221953280041975323323006976000000000000000000000000000000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Matthew Campbell, Table of n, a(n) for n = 0..10 FORMULA a(n) = A007955(A000142(n)). a(n) = (n!)^(d(n!)/2) = (A000142(n))^(A000005(A000142(n))/2). MAPLE A280420 := proc(n) mul(d, d=numtheory[divisors](n!)) ; end proc: # R. J. Mathar, Jan 04 2017 MATHEMATICA Table[(n!)^(DivisorSigma[0, n!]/2), {n, 0, 10}] PROG (Python) from math import isqrt, factorial from sympy import divisor_count def A280420(n): return (lambda m:isqrt(m)**c if (c:=divisor_count(m)) & 1 else m**(c//2))(factorial(n)) # Chai Wah Wu, Jun 25 2022 CROSSREFS Cf. A000005, A000142, A007955, A027423. Sequence in context: A181555 A306644 A283261 * A051459 A358972 A073581 Adjacent sequences: A280417 A280418 A280419 * A280421 A280422 A280423 KEYWORD nonn AUTHOR Matthew Campbell, Jan 02 2017 STATUS approved

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Last modified April 14 14:16 EDT 2024. Contains 371665 sequences. (Running on oeis4.)