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A069144
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Numbers k such that A068976(k) divides k.
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1
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1, 2, 12, 40, 120, 208, 280, 396, 440, 520, 624, 672, 680, 760, 920, 1040, 1160, 1240, 1456, 1480, 1640, 1720, 1880, 2120, 2288, 2360, 2440, 2680, 2840, 2920, 3120, 3160, 3320, 3360, 3392, 3536, 3560, 3880, 3952, 3960, 4040, 4120, 4280, 4360, 4368, 4520
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OFFSET
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1,2
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COMMENTS
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For n > 4 A068976(a(n)) >= 40 and almost all terms k in the sequence are such that A068976(k) = 40.
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LINKS
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MATHEMATICA
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f[p_, e_] := If[OddQ[e], 2*(p^(e + 1) - 1)/(p^2 - 1), (p^(e + 2) + p^e - 2)/(p^2 - 1)]; s[1] = 1; s[n_] := Times @@ (f @@@ FactorInteger[n]); Select[Range[5000], Divisible[#, s[#]] &] (* Amiram Eldar, Sep 03 2020 *)
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PROG
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(PARI) for(n=1, 10000, if(n%sumdiv(n, d, d/core(d))==0, print1(n, ", ")))
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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