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 A015917 #25 Oct 18 2022 01:52:18 %S A015917 5,7,11,17,19,29,31,41,47,59,61,65,67,71,89,97,101,127,137,139,151, %T A015917 167,170,179,181,199,209,211,227,229,239,251,257,269,271,281,337,347, %U A015917 367,389,397,409,419,421,431,449,467,479,487,491,509,557,587 %N A015917 Numbers k such that sigma(k) + 12 = sigma(k+12). %H A015917 Vincenzo Librandi, <a href="/A015917/b015917.txt">Table of n, a(n) for n = 1..1000</a> %t A015917 Select[Range[600],DivisorSigma[1,#]+12==DivisorSigma[1,#+12]&] (* _Harvey P. Dale_, Oct 14 2012 *) %o A015917 (PARI) is(n)=sigma(n)+12==sigma(n+12) \\ _Charles R Greathouse IV_, Mar 09 2014 %Y A015917 Cf. A000203. %Y A015917 Union of A046133 and A054902. %K A015917 nonn %O A015917 1,1 %A A015917 _Robert G. Wilson v_