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A027430
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Number of distinct products ijk with 1 <= i<j<k <= n.
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27
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0, 0, 1, 4, 10, 16, 29, 42, 60, 75, 111, 126, 177, 206, 238, 274, 361, 396, 507, 554, 613, 677, 838, 883, 1004, 1092, 1198, 1277, 1529, 1590, 1881, 1998, 2133, 2275, 2432, 2518, 2921, 3096, 3278, 3391, 3884, 4014, 4563, 4750, 4938, 5186, 5840, 5987, 6422, 6652
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OFFSET
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1,4
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REFERENCES
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Amarnath Murthy, Generalization of partition function introducing Smarandache Factor Partitions, Smarandache Notions Journal, 1-2-3, Vol. 11, 2000.
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LINKS
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FORMULA
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MATHEMATICA
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nn = 50;
prod = Table[0, {1 + nn^3}];
a[1] = 0;
a[n_] := (Do[prod[[1 + i*j*k]] = 1, {i, 0, n}, {j, i+1, n}, {k, j+1, n}]; Count[Take[prod, 1 + n^3], 1] - 1);
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PROG
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(Haskell)
import Data.List (nub)
a027430 n = length $ nub [i*j*k | k<-[3..n], j<-[2..k-1], i<-[1..j-1]]
(Python)
def A027430(n): return len({i*j*k for i in range(1, n+1) for j in range(1, i) for k in range(1, j)}) # Chai Wah Wu, Oct 16 2023
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CROSSREFS
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Number of terms in row n of A083507.
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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