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A331845
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Number of compositions (ordered partitions) of n into distinct cubes.
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7
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1, 1, 0, 0, 0, 0, 0, 0, 1, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 0, 0, 0, 0, 0, 0, 2, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 0, 0, 0, 0, 0, 0, 2, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 6, 0, 0, 0, 0, 0, 0, 6, 24
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OFFSET
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0,10
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LINKS
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EXAMPLE
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a(36) = 6 because we have [27,8,1], [27,1,8], [8,27,1], [8,1,27], [1,27,8] and [1,8,27].
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MAPLE
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b:= proc(n, i, p) option remember;
`if`((i*(i+1)/2)^2<n, 0, `if`(n=0, p!,
`if`(i^3>n, 0, b(n-i^3, i-1, p+1))+b(n, i-1, p)))
end:
a:= n-> b(n, iroot(n, 3), 0):
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MATHEMATICA
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b[n_, i_, p_] := b[n, i, p] = If[(i(i+1)/2)^2 < n, 0, If[n == 0, p!, If[i^3 > n, 0, b[n-i^3, i-1, p+1]] + b[n, i-1, p]]];
a[n_] := b[n, Floor[n^(1/3)], 0];
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CROSSREFS
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Cf. A000578, A023358, A032020, A032021, A032022, A218396, A219107, A279329, A331843, A331844, A331846, A331847.
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KEYWORD
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AUTHOR
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STATUS
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approved
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