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A100436
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Number of distinct products i*j*k for 1 <= i < j <= k <= n.
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5
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0, 1, 4, 10, 20, 27, 46, 61, 84, 101, 147, 163, 226, 256, 292, 331, 434, 472, 601, 655, 719, 785, 968, 1016, 1143, 1233, 1346, 1433, 1713, 1778, 2099, 2219, 2363, 2509, 2677, 2763, 3202, 3381, 3573, 3690, 4223, 4360, 4951, 5149, 5347, 5598, 6298, 6449
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OFFSET
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1,3
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LINKS
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MAPLE
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f:=proc(n) local i, j, k, t1; t1:={}; for i from 1 to n-1 do for j from i+1 to n do for k from j to n do t1:={op(t1), i*j*k}; od: od: od: t1:=convert(t1, list); nops(t1); end;
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MATHEMATICA
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f[n_] := Length[ Union[ Flatten[ Table[ i*j*k, {i, n}, {j, i + 1, n}, {k, j, n}]]]]; Table[ f[n], {n, 48}] (* Robert G. Wilson v, Dec 14 2004 *)
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PROG
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(Python)
def A100436(n): return len({i*j*k for i in range(1, n+1) for j in range(1, i+1) for k in range(1, j)}) # Chai Wah Wu, Oct 16 2023
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CROSSREFS
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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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