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 A067135 #35 May 09 2025 07:13:33
%S A067135 5,13,313,1153,26206,100318,111928,160873,363283,644278,1676428,
%T A067135 2097808,2639518,3875998,5349238,5738773,5903638,6045583,11272903,
%U A067135 13192933,17242333,18234403,19667998,29520643,29595193,31944238,36918448,37049803,37201813,43522288
%N A067135 Numbers k such that sigma(k+2) = 2*sigma(k-2).
%C A067135 For each term given here except 5, k+2 is divisible by 3, but that is not always true: k = 149784995358 is a counterexample. Also, k+2 is divisible by 5 for all terms here except 5 and 26206, but it is also not true for k = 70333261.
%H A067135 Donovan Johnson, <a href="/A067135/b067135.txt">Table of n, a(n) for n = 1..500</a> (first 80 terms from Vincenzo Librandi)
%t A067135 Do[If[DivisorSigma[1, n+2] == 2*DivisorSigma[1, n-2], Print[n]], {n, 2, 10^9}] (* _Ryan Propper_, Sep 26 2005 *)
%o A067135 (PARI) isok(k) = k > 2 && sigma(k+2) == 2*sigma(k-2); \\ _Amiram Eldar_, May 09 2025
%Y A067135 Cf. A000203 (sigma), A067134.
%K A067135 nonn
%O A067135 1,1
%A A067135 _Benoit Cloitre_, Feb 18 2002
%E A067135 Edited by _Dean Hickerson_, Feb 20 2002
%E A067135 More terms from _Ryan Propper_, Sep 26 2005