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 A069059 #26 May 23 2022 11:46:14
%S A069059 6,10,12,14,15,18,20,22,24,26,28,30,33,34,38,40,42,44,45,46,48,51,52,
%T A069059 54,56,58,60,62,66,68,69,70,72,74,76,78,80,82,84,86,87,88,90,91,92,94,
%U A069059 95,96,99,102,104,105,106,108,110,112,114,116,117,118,120,122,123,124
%N A069059 Numbers k such that k and sigma(k) are not relatively prime.
%C A069059 Complement of A014567(n).
%C A069059 Also, numbers n such that the reduced denominator of Sum_{d|n} 1/d (A017666) is less than n. - _Ivan Neretin_, Aug 30 2015
%C A069059 The asymptotic density of this sequence is 1 (Dressler, 1974; Luca, 2007). - _Amiram Eldar_, May 23 2022
%H A069059 Reinhard Zumkeller, <a href="/A069059/b069059.txt">Table of n, a(n) for n = 1..10000</a>
%H A069059 Robert E. Dressler, <a href="https://doi.org/10.4153/CMB-1974-019-5">On a theorem of Niven</a>, Canadian Mathematical Bulletin, Vol. 17, No. 1 (1974), pp. 109-110.
%H A069059 Florian Luca, <a href="http://projecteuclid.org/euclid.mjms/1316032973">On the densities of some subsets of integers</a>, Missouri Journal of Mathematical Sciences, Vol. 19, No. 3 (2007), pp. 167-170.
%F A069059 A009194(a(n)) > 1. - _Reinhard Zumkeller_, Mar 23 2013
%p A069059 select(n -> igcd(n,numtheory:-sigma(n)) > 1, [$1..1000]); # _Robert Israel_, Sep 01 2015
%t A069059 Select[Range@125, GCD[#, DivisorSigma[1, #]] > 1 &] (* _Ivan Neretin_, Aug 30 2015 *)
%o A069059 (PARI) for(n=1,160,if(gcd(sigma(n),n)>1,print1(n,",")))
%o A069059 (Haskell)
%o A069059 a069059 n = a069059_list !! (n-1)
%o A069059 a069059_list = filter ((> 1) . a009194) [1..]
%o A069059 -- _Reinhard Zumkeller_, Mar 23 2013
%Y A069059 Cf. A000203, A009194, A014567, A017666.
%K A069059 easy,nonn
%O A069059 1,1
%A A069059 _Benoit Cloitre_, Apr 04 2002