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 A325312 #16 Apr 05 2024 04:46:27
%S A325312 105,315,495,735,945,1155,1485,1995,2205,2415,2625,2835,2925,3135,
%T A325312 3255,3315,3465,3795,4455,4515,4935,5115,5145,5445,5655,5985,6195,
%U A325312 6615,6825,7035,7095,7245,7455,7605,7755,7875,8085,8295,8505,8715,8775,8925,9009,9405,9735,9765,9945,10395,10725,10815,11235,11385,11781,12375
%N A325312 Odd numbers k for which sigma(k^2) == 3 (mod 4) and sigma(k^2) > 2*k^2.
%C A325312 Square roots of A325311, odd abundant numbers k for which sigma(k) == 3 mod 4.
%H A325312 Antti Karttunen, <a href="/A325312/b325312.txt">Table of n, a(n) for n = 1..10000</a>
%H A325312 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>.
%F A325312 a(n) = sqrt(A325311(n)).
%t A325312 Select[Range[1, 12375 , 2], Mod[(s = DivisorSigma[1, #^2]), 4] == 3 && s > 2*#^2 &] (* _Amiram Eldar_, Apr 05 2024 *)
%o A325312 (PARI) isA325312(n) = { my(t=sigma(n*n)); (n%2 && 3==(t%4) && t>(2*n*n)); };
%Y A325312 Cf. A000196, A325311.
%Y A325312 Intersection of A174830 and A324909.
%K A325312 nonn
%O A325312 1,1
%A A325312 _Antti Karttunen_, Apr 20 2019