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 A174435 #11 Feb 24 2021 03:55:24 %S A174435 1,1,1,1,1,2,1,1,1,1,1,2,1,1,3,1,1,1,2,2,3,1,1,1,1,3,1,2,1,1,1,2,1,1, %T A174435 2,1,1,3,2,4,2,1,1,1,1,1,1,1,4,2,2,1,1,1,1,1,1,1,1,2,3,2,1,4,3,1,2,1, %U A174435 1,9,2,1,1,1,1,2,1,1,1,1,1,2,1,2,5,1,3,3,1,2,1,2,2,1,1,8,1,1,1,6 %N A174435 lambda(y)/x, where y an odd squarefree semiprime and x = ord(2,y) the smallest positive integer such that 2^x == 1 mod y (the multiplicative order of 2 mod y). %H A174435 Vassilis Papadimitriou, <a href="/A174435/b174435.txt">Table of n, a(n) for n=1,...,10000</a>. %F A174435 Equals lambda(A046388)/ord(2, A046388), or lambda(A046388)/A174240. %F A174435 a(n) = A002322(A046388(n))/A002326((A046388(n)+1)/2). - _Amiram Eldar_, Feb 24 2021 %e A174435 For n=1 the a(1)= 1, as the first odd squarefree semiprime is 15, lambda(15)=4 and ord(2,15)=4 %t A174435 (CarmichaelLambda[#]/MultiplicativeOrder[2, #]) & /@ Select[Range[1, 530, 2], PrimeOmega[#] == 2 && PrimeNu[#] == 2 &] (* _Amiram Eldar_, Feb 24 2021 *) %Y A174435 Cf. A002322, A002326, A046388, A174240. %K A174435 nonn %O A174435 1,6 %A A174435 _Vassilis Papadimitriou_, Mar 19 2010