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 A351536 #9 Feb 13 2022 13:38:32
%S A351536 13,37,61,73,97,109,153,157,181,193,229,241,277,313,325,337,349,373,
%T A351536 397,409,421,433,457,541,577,601,613,661,673,709,733,757,769,801,829,
%U A351536 853,877,925,937,997,1009,1021,1033,1069,1093,1117,1129,1153,1201,1213,1237,1249,1297,1321,1381,1429,1453,1489,1525,1549
%N A351536 Odd numbers for which sigma(k) is congruent to 2 modulo 4 and the 3-adic valuations of k and sigma(k) are equal.
%H A351536 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%t A351536 Select[Range[1, 1500, 2], Mod[(s = DivisorSigma[1, #]), 4] == 2 && Equal @@ IntegerExponent[{#, s}, 3] &] (* _Amiram Eldar_, Feb 13 2022 *)
%o A351536 (PARI) isA351536(n) = if(!(n%2),0,my(s=sigma(n)); (2 == (s%4)) && (valuation(n,3) == valuation(s,3)));
%Y A351536 Intersection of A191218 and A349749. Cf. A349755 (subsequence).
%Y A351536 Cf. A000203, A007949, A351534.
%K A351536 nonn
%O A351536 1,1
%A A351536 _Antti Karttunen_, Feb 13 2022