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A080511
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Triangle whose n-th row contains the least set (ordered lexicographically) of n distinct positive integers whose arithmetic mean is an integer.
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4
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1, 1, 3, 1, 2, 3, 1, 2, 3, 6, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 9, 1, 2, 3, 4, 5, 6, 7, 1, 2, 3, 4, 5, 6, 7, 12, 1, 2, 3, 4, 5, 6, 7, 8, 9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 15, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 18, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 21
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OFFSET
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1,3
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COMMENTS
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The n-th row is {1,2,...,n-1,x}, where x=n if n is odd, x=3n/2 if n is even.
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LINKS
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EXAMPLE
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Triangle starts:
1;
1, 3;
1, 2, 3;
1, 2, 3, 6;
1, 2, 3, 4, 5;
1, 2, 3, 4, 5, 9;
1, 2, 3, 4, 5, 6, 7;
1, 2, 3, 4, 5, 6, 7, 12;
...
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MAPLE
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T:= proc(n) $1..n-1, `if`(irem(n, 2)=1, n, 3*n/2) end:
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MATHEMATICA
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row[n_] := Append[Range[n - 1], If[OddQ[n], n, 3 n/2]];
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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