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A056925
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Largest integer power of n which divides product of divisors of n.
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3
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1, 2, 3, 4, 5, 36, 7, 64, 9, 100, 11, 1728, 13, 196, 225, 256, 17, 5832, 19, 8000, 441, 484, 23, 331776, 25, 676, 729, 21952, 29, 810000, 31, 32768, 1089, 1156, 1225, 1679616, 37, 1444, 1521, 2560000, 41, 3111696, 43, 85184, 91125, 2116, 47
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OFFSET
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1,2
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COMMENTS
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Product of the distinct parts in the divisor pairs (d,n/d) of n, where d < n/d. For example, the divisors of n = 4 are {1,2,4} with divisor pairs (1,4) and (2,2), but only the pair (1,4) has distinct parts, so a(4) = 1*4 = 4. - Wesley Ivan Hurt, Nov 10 2023
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LINKS
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FORMULA
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If n is a square a(n) = A007955(n)/sqrt(n), otherwise a(n) = A007955(n).
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EXAMPLE
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a(16)=256 since the factors of 16 are 1,2,4,8,16, their product is 1024 and the largest power of 16 which divides 1024 is 256.
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MATHEMATICA
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lip[n_]:=Module[{pr=Times@@Divisors[n], pwr}, pwr= Floor[ Log[n, pr]]; n^Last[Select[Range[pwr], Divisible[pr, n^#]&]]]; Join[{1}, lip/@ Range[2, 50]] (* Harvey P. Dale, Apr 02 2011 *)
a[n_] := n^Floor[DivisorSigma[0, n]/2]; Array[a, 50] (* Amiram Eldar, Jun 26 2022 *)
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PROG
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(Python)
from sympy import divisor_count
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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