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A046683 Numbers k such that the sum of squares of divisors of k and sum of cubes of divisors of k are relatively prime. 7
1, 2, 4, 9, 18, 25, 36, 100, 121, 225, 289, 484, 529, 841, 900, 1089, 1156, 1681, 2116, 2209, 2601, 2809, 3364, 3481, 4356, 4761, 5041, 6724, 6889, 7225, 7569, 7921, 8836, 10201, 10404, 11236, 11449, 12769, 13225, 13924, 15129, 17161, 18769, 19044 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
It can be shown that this is a subsequence of A028982.
LINKS
MATHEMATICA
sdcdQ[n_]:=Module[{d=Divisors[n]}, CoprimeQ[Total[d^2], Total[d^3]]]; Select[ Range[ 20000], sdcdQ] (* Harvey P. Dale, Apr 09 2018 *)
PROG
(PARI) isok(n) = gcd(sigma(n, 2), sigma(n, 3)) == 1; \\ Michel Marcus, Sep 24 2019
CROSSREFS
Sequence in context: A283315 A024425 A034685 * A065055 A065030 A103321
KEYWORD
nonn
AUTHOR
STATUS
approved

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Last modified February 21 13:52 EST 2024. Contains 370235 sequences. (Running on oeis4.)