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 A337196 #15 Feb 22 2021 21:20:03 %S A337196 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0, %T A337196 0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,2,0, %U A337196 0,0,0,0,0,0,0,2,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 %N A337196 The 3-adic valuation of 1+A000265(sigma(n)), where A000265 gives the odd part. %H A337196 Antti Karttunen, <a href="/A337196/b337196.txt">Table of n, a(n) for n = 1..65537</a> %H A337196 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a> %F A337196 a(n) = A007949(A337194(n)) = A007949(1+A000265(A000203(n))). %F A337196 a(n) = A007949(A336698(n)). %t A337196 Array[IntegerExponent[1 + #/2^IntegerExponent[#, 2], 3] &@ DivisorSigma[1, #] &, 105] (* _Michael De Vlieger_, Feb 22 2021 *) %o A337196 (PARI) %o A337196 A007949(n) = valuation(n,3); %o A337196 A000265(n) = (n>>valuation(n,2)); %o A337196 A337196(n) = A007949(1+A000265(sigma(n))); %Y A337196 Cf. A000203, A000265, A007949, A074941, A161942, A336698, A336700, A337194, A337195. %Y A337196 Cf. A337197 (the first occurrence of each n). %K A337196 nonn %O A337196 1,67 %A A337196 _Antti Karttunen_, Aug 18 2020