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A332002
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Number of compositions (ordered partitions) of n into distinct parts all relatively prime to n.
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2
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1, 1, 0, 2, 2, 4, 2, 12, 4, 6, 4, 64, 4, 132, 6, 32, 32, 616, 6, 1176, 32, 120, 58, 4756, 32, 3452, 108, 1632, 132, 30460, 8, 55740, 376, 3872, 352, 18864, 132, 315972, 1266, 13368, 352, 958264, 108, 1621272, 2228, 10176, 6166, 4957876, 352, 2902866, 2132
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OFFSET
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0,4
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LINKS
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EXAMPLE
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a(9) = 6 because we have [8, 1], [7, 2], [5, 4], [4, 5], [2, 7] and [1, 8].
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MAPLE
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a:= proc(n) local b; b:=
proc(m, i, p) option remember; `if`(m=0, p!, `if`(i<1, 0,
b(m, i-1, p)+`if`(i>m or igcd(i, n)>1, 0, b(m-i, i-1, p+1))))
end; forget(b): b(n$2, 0)
end:
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MATHEMATICA
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a[n_] := Module[{b}, b[m_, i_, p_] := b[m, i, p] = If[m == 0, p!, If[i < 1, 0, b[m, i-1, p] + If[i > m || GCD[i, n] > 1, 0, b[m-i, i-1, p+1]]]]; b[n, n, 0]];
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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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