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1, 2, 1, 3, 2, 1, 5, 2, 3, 1, 7, 2, 1, 11, 2, 3, 5, 4, 3, 7, 2, 13, 1, 17, 2, 15, 1, 19, 2, 1, 23, 2, 9, 1, 5, 7, 6, 1, 29, 2, 5, 11, 3, 13, 4, 11, 7, 1, 31, 2, 5, 13, 6, 1, 37, 2, 7, 3, 17, 4, 15, 1, 41, 2, 1, 43, 2, 33, 1, 47, 2, 35, 3, 19, 4, 3, 23, 4, 5
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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LINKS
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FORMULA
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GCD(a(n), a(n+1)) = 1.
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EXAMPLE
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MATHEMATICA
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terms = 100;
rad[n_] := Times @@ FactorInteger[n][[All, 1]];
A280864 = Reap[present = 0; p = 1; pp = 1;
Do[forbidden = GCD[p, pp]; mandatory = p/forbidden;
a = mandatory;
While[BitGet[present, a] > 0 || GCD[forbidden, a] > 1,
a += mandatory];
Sow[a];
present += 2^a; pp = p; p = rad[a],
{terms}]][[2, 1]];
Clear[a];
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PROG
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(PARI) \\ See Links section.
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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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