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 A172335 #20 Aug 16 2025 15:26:39 %S A172335 142,238,418,429,598,622,2985,3502,16269,22678,23188,27778,38494, %T A172335 46761,48489,62235,74188,98745,110170,120345,129448,151677,187822, %U A172335 190888,194818,205185,223685,235438,246934,249166 %N A172335 Numbers k such that k and k+17 have same sum of divisors. %D A172335 M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 840. %D A172335 J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 62, p. 22, Ellipses, Paris 2008. %D A172335 W. Sierpiński, A Selection of Problems in the Theory of Numbers. Macmillan, NY, 1964, p. 110. %H A172335 Amiram Eldar, <a href="/A172335/b172335.txt">Table of n, a(n) for n = 1..500</a> %H A172335 M. Abramowitz and I. A. Stegun, eds., <a href="http://www.convertit.com/Go/ConvertIt/Reference/AMS55.ASP">Handbook of Mathematical Functions</a>, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy]. %p A172335 with(numtheory):for n from 1 to 250000 do;if sigma(n) = sigma(n+17) then print(n); else fi ; od; %t A172335 Select[Range[10^5], DivisorSigma[1, #] == DivisorSigma[1, # + 17] &] (* _Amiram Eldar_, Aug 11 2019 *) %o A172335 (Magma) [m:m in [1..250000]| SumOfDivisors(m) eq SumOfDivisors(m+17)]; // _Marius A. Burtea_, Aug 11 2019 %Y A172335 Cf. A000203. %K A172335 nonn %O A172335 1,1 %A A172335 _Michel Lagneau_, Feb 01 2010