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A348934 Numbers k congruent to 1 or 5 mod 6, for which A348930(k^2) > k^2. 2

%I #10 Nov 04 2021 20:47:21

%S 5,11,17,23,25,29,41,47,49,53,55,59,71,83,85,89,101,107,113,115,121,

%T 125,131,137,145,149,167,169,173,179,187,191,197,205,227,233,235,239,

%U 245,251,253,257,263,265,269,275,281,289,293,295,311,317,319,343,347,353,355,359,361,383,389,391,401,415,419,425,431

%N Numbers k congruent to 1 or 5 mod 6, for which A348930(k^2) > k^2.

%C See comments in A348933.

%H <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>

%t s[n_] := n / 3^IntegerExponent[n, 3]; Select[Range[450], MemberQ[{1, 5}, Mod[#, 6]] && s[DivisorSigma[1, #^2]] > #^2 &] (* _Amiram Eldar_, Nov 04 2021 *)

%o (PARI)

%o A038502(n) = (n/3^valuation(n, 3));

%o A348930(n) = A038502(sigma(n));

%o isA348934(n) = ((n%2)&&(n%3)&&(A348930(n^2)>(n^2)));

%Y Cf. A348930, A348932, A348933, A348936.

%K nonn

%O 1,1

%A _Antti Karttunen_, Nov 04 2021

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Last modified April 24 03:08 EDT 2024. Contains 371918 sequences. (Running on oeis4.)