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 A015882 #29 Feb 10 2024 11:36:07 %S A015882 35,104,285,287,310,329,340,345,406,609,660,736,767,957,1067,1207, %T A015882 1242,1768,1786,1817,1824,2047,2288,2407,2672,2686,2714,3009,4012, %U A015882 4387,4653,4847,6179,7532,8366,8920,10005,10528,11140,11670,11951 %N A015882 Numbers k such that sigma(k) = sigma(k+12). %H A015882 Donovan Johnson, <a href="/A015882/b015882.txt">Table of n, a(n) for n = 1..1000</a> %H A015882 A. Weingartner, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL14/Weingartner/wein3.html">On the Solutions of sigma(n) = sigma(n+k)</a>, Journal of Integer Sequences, Vol. 14 (2011), #11.5.5. %t A015882 Select[Range[20000], DivisorSigma[1, #]==DivisorSigma[1, # + 12] &] (* _Vincenzo Librandi_, Mar 10 2014 *) %o A015882 (PARI) is(n)=sigma(n)==sigma(n+12) \\ _Charles R Greathouse IV_, Mar 09 2014 %Y A015882 Cf. A002961, A007373, A015861, A015863, A015865, A015866, A015867, A015876, A015877, A015880, A015881, A015883, A181647. %K A015882 nonn %O A015882 1,1 %A A015882 _Robert G. Wilson v_