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 A015867 #28 Feb 10 2024 11:35:28 %S A015867 10,62,188,362,759,1178,1214,1431,1442,1598,1695,1748,2235,3495,6699, %T A015867 9338,9945,11438,13695,18795,20727,26199,26631,30548,35438,53751, %U A015867 79826,79827,89378,103887,114231,122738,132111,135506,138135 %N A015867 Numbers k such that sigma(k) = sigma(k+7). %D A015867 J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 62, p. 22, Ellipses, Paris 2008. %H A015867 Donovan Johnson, <a href="/A015867/b015867.txt">Table of n, a(n) for n = 1..1000</a> %t A015867 Select[Range[140000], DivisorSigma[1, #]==DivisorSigma[1, # + 7] &] (* _Vincenzo Librandi_, Mar 10 2014 *) %o A015867 (PARI) is(n)=sigma(n)==sigma(n+7) \\ _Charles R Greathouse IV_, Mar 09 2014 %Y A015867 Cf. A002961, A007373, A015861, A015863, A015865, A015866, A015876, A015877, A015880, A015881, A015882, A015883, A181647. %K A015867 nonn %O A015867 1,1 %A A015867 _Robert G. Wilson v_