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A026793
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Juxtaposed partitions of 1,2,3,... into distinct parts, ordered by number of terms and then lexicographically.
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17
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1, 2, 3, 1, 2, 4, 1, 3, 5, 1, 4, 2, 3, 6, 1, 5, 2, 4, 1, 2, 3, 7, 1, 6, 2, 5, 3, 4, 1, 2, 4, 8, 1, 7, 2, 6, 3, 5, 1, 2, 5, 1, 3, 4, 9, 1, 8, 2, 7, 3, 6, 4, 5, 1, 2, 6, 1, 3, 5, 2, 3, 4, 10, 1, 9, 2, 8, 3, 7, 4, 6, 1, 2, 7, 1, 3, 6, 1, 4, 5, 2, 3, 5, 1, 2, 3, 4, 11, 1, 10, 2, 9, 3, 8, 4, 7, 5, 6, 1, 2, 8, 1, 3, 7, 1, 4, 6, 2, 3, 6, 2, 4
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OFFSET
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1,2
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COMMENTS
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LINKS
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M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy].
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EXAMPLE
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The partitions of 5 into distinct parts are [5], [1,4] and [2,3], so row 5 is 5,1,4,2,3.
Triangle begins:
[1];
[2];
[3], [1,2];
[4], [1,3];
[5], [1,4], [2,3];
[6], [1,5], [2,4], [1,2,3];
[7], [1,6], [2,5], [3,4], [1,2,4];
[8], [1,7], [2,6], [3,5], [1,2,5], [1,3,4];
[9], [1,8], [2,7], [3,6], [4,5], [1,2,6], [1,3,5], [2,3,4];
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MAPLE
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b:= proc(n, i) b(n, i):= `if`(n=0, [[]], `if`(i>n, [],
[map(x->[i, x[]], b(n-i, i+1))[], b(n, i+1)[]]))
end:
T:= n-> map(x-> x[], sort(b(n, 1)))[]:
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MATHEMATICA
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Array[SortBy[Map[Reverse, Select[IntegerPartitions[#], UnsameQ @@ # &]], Length] &, 12] // Flatten (* Michael De Vlieger, Jun 22 2020 *)
b[n_, i_] := b[n, i] = If[n == 0, {{}}, If[i>n, {}, Join[Prepend[#, i]& /@ b[n-i, i+1], b[n, i+1]]]];
T[n_] := Sort[b[n, 1]];
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CROSSREFS
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KEYWORD
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nonn,tabf
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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