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 A082506 #8 May 31 2018 21:39:13 %S A082506 2,1,1,2,1,4,1,4,1,2,1,8,1,8,1,8,1,4,1,4,1,4,1,16,1,2,1,16,1,2,1,16,1, %T A082506 2,1,8,1,4,1,8,1,2,1,8,1,8,1,32,1,2,1,4,1,4,1,32,1,2,1,4,1,32,1,32,1, %U A082506 2,1,4,1,2,1,16,1,2,1,8,1,2,1,16,1,2,1,4,1,4,1,16,1,2,1,16,1,16,1,64,1,8,1 %N A082506 a(n) = gcd(2^n, n - phi(n)); largest power of 2 dividing cototient(n) = A051953(n). %C A082506 a(n)=1 if and only if n is odd or n = 2. - _Robert Israel_, May 31 2018 %H A082506 Robert Israel, <a href="/A082506/b082506.txt">Table of n, a(n) for n = 1..10000</a> %e A082506 Different from A069177, analogous sequence with totient, instead of cototient. %p A082506 f:= n -> padic:-ordp(n - numtheory:-phi(n), 2): %p A082506 map(f, [$1..100]); # _Robert Israel_, May 31 2018 %Y A082506 Cf. A000010, A051953, A009195, A083250, A007283, A050339, A053576, A069177. %K A082506 nonn %O A082506 1,1 %A A082506 _Labos Elemer_, Apr 28 2003