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A076994
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a(1) = 2, a(n+1) is the largest squarefree number < 2a(n).
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1
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2, 3, 5, 7, 13, 23, 43, 85, 167, 331, 661, 1321, 2641, 5281, 10561, 21121, 42241, 84481, 168961, 337921, 675841, 1351681, 2703361, 5406721, 10813441, 21626881, 43253761, 86507521, 173015041, 346030081, 692060161, 1384120321, 2768240641
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OFFSET
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1,1
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COMMENTS
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Analogous to Bertrand's primes.
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LINKS
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MAPLE
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with(numtheory):a[1] := 2:for n from 2 to 84 do q := 2*a[n-1]-1:while(not issqrfree(q)) do q := q-1:od:a[n] := q:od:seq(a[l], l=1..84);
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MATHEMATICA
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lsfn[n_]:=Module[{s=2n-1}, While[!SquareFreeQ[s], s--]; s]; NestList[ lsfn, 2, 40] (* Harvey P. Dale, Nov 28 2018 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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