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A318871
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Minimum Heinz number of a factorization of n into factors > 1.
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18
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1, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 35, 41, 43, 47, 49, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271
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OFFSET
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1,2
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COMMENTS
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The Heinz number of an integer partition (y_1, ..., y_k) is prime(y_1) * ... * prime(y_k).
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LINKS
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Table of n, a(n) for n=1..58.
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MAPLE
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a:= proc(n) option remember; `if`(n=1, 1, min(ithprime(n),
seq(ithprime(d)*a(n/d), d=numtheory[divisors](n) minus {1, n})))
end:
seq(a(n), n=1..60); # Alois P. Heinz, Sep 05 2018
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MATHEMATICA
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facs[n_]:=If[n<=1, {{}}, Join@@Table[(Prepend[#1, d]&)/@Select[facs[n/d], Min@@#1>=d&], {d, Rest[Divisors[n]]}]];
Table[Min[Times@@Prime/@#&/@facs[n]], {n, 100}]
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CROSSREFS
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Cf. A000040, A001055, A007716, A056239, A064988, A162247, A215366, A246868.
Sequence in context: A242393 A210494 A338483 * A330225 A275938 A093893
Adjacent sequences: A318868 A318869 A318870 * A318872 A318873 A318874
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KEYWORD
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nonn
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AUTHOR
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Gus Wiseman, Sep 05 2018
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STATUS
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approved
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