This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A348933 #13 Nov 04 2021 20:47:15
%S A348933 7,13,19,31,35,37,43,61,65,67,73,77,79,91,95,97,103,109,119,127,133,
%T A348933 139,143,151,155,157,161,163,175,181,185,193,199,203,209,211,215,217,
%U A348933 221,223,229,241,247,259,271,277,283,287,299,301,305,307,313,323,325,329,331,335,337,341,349,365,367,371,373,377,379
%N A348933 Numbers k congruent to 1 or 5 mod 6, for which A348930(k^2) < k^2.
%C A348933 Any hypothetical odd term y of A005820 must by necessity be a square. If y is also a nonmultiple of 3, then the square root x = A000196(y) of such a number y must satisfy the condition that for all nontrivial unitary divisor pairs d and x/d [with gcd(d,x/d) = 1, 1 < d < x], the other divisor should reside in this sequence, and the other divisor in A348934. The explanation is similar to the one given in A348738. See also comments in A348935.
%H A348933 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%t A348933 s[n_] := n / 3^IntegerExponent[n, 3]; Select[Range[400], MemberQ[{1, 5}, Mod[#, 6]] && s[DivisorSigma[1, #^2]] < #^2 &] (* _Amiram Eldar_, Nov 04 2021 *)
%o A348933 (PARI)
%o A348933 A038502(n) = (n/3^valuation(n, 3));
%o A348933 A348930(n) = A038502(sigma(n));
%o A348933 isA348933(n) = ((n%2)&&(n%3)&&(A348930(n^2)<(n^2)));
%Y A348933 Cf. A000196, A005820, A348738, A348930, A348931, A348934, A348935.
%K A348933 nonn
%O A348933 1,1
%A A348933 _Antti Karttunen_, Nov 04 2021