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 A308423 Product of divisors of multiply-perfect numbers. 1
 1, 36, 21952, 42998169600000000, 30019840638976, 8480691722056324948490652657647616, 2343612817652433441167245312 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS a(8) has 216 digits (116929951...000000000). Supersequence of A067584. LINKS FORMULA a(n) = A007955(A007691(n)). EXAMPLE For n = 3; a(3) = A007955(A007691(3)) = A007955(28) = 21952. MATHEMATICA s = {}; Do[If[Divisible[DivisorSigma[1, n], n], AppendTo[s, n^(DivisorSigma[0, n]/2)]], {n, 10^4}]; s (* Amiram Eldar, Jul 04 2019 *) PROG (MAGMA) [&*[d: d in Divisors(m)]: m in [1..10^5] | IsIntegral(SumOfDivisors(m)/m)] CROSSREFS Cf. A007691, A007955, A067584. See A088843 and A307741 for the number of and the sum of divisors of multiply-perfect numbers. Sequence in context: A271338 A001308 A067584 * A146521 A159431 A028454 Adjacent sequences:  A308420 A308421 A308422 * A308424 A308425 A308426 KEYWORD nonn AUTHOR Jaroslav Krizek, May 26 2019 STATUS approved

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Last modified January 16 23:43 EST 2022. Contains 350377 sequences. (Running on oeis4.)