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 A357014 #9 Sep 09 2022 06:30:46 %S A357014 1,3,5,7,11,13,15,17,19,21,23,29,31,33,35,37,39,41,43,47,51,53,55,57, %T A357014 59,61,65,67,69,71,73,77,79,81,83,85,87,89,91,93,95,97,101,103,105, %U A357014 107,109,111,113,115,119,123,127,129,131,133,137,139,141,143,145,149 %N A357014 Numbers whose sum of exponential divisors (A051377) is odd. %C A357014 Includes all the odd squarefree numbers (A056911). First differs from this sequence at n = 34. %C A357014 Equivalently, the odd terms of A197680, i.e., odd numbers with an odd number of exponential divisors (A049419). %C A357014 The asymptotic density of this sequence is 0.409797... (A357017). %H A357014 Amiram Eldar, <a href="/A357014/b357014.txt">Table of n, a(n) for n = 1..10000</a> %e A357014 1 is a term since A051377(1) = 1 is odd. %e A357014 3 is a term since A051377(3) = 3 is odd. %t A357014 f[p_, e_] := DivisorSum[e, p^# &]; esigma[1] = 1; esigma[n_] := Times @@ f @@@ FactorInteger[n]; Select[Range[150], OddQ[esigma[#]] &] %Y A357014 Cf. A049419, A051377, A357017. %Y A357014 Subsequence of A197680. %Y A357014 Subsequences: A056911, A357015. %Y A357014 Similar sequences: A000079 (numbers with an odd sum of unitary divisors), A028982 (numbers with an odd sum of divisors). %K A357014 nonn %O A357014 1,2 %A A357014 _Amiram Eldar_, Sep 09 2022