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 A276504 #12 Sep 08 2022 08:46:17 %S A276504 7,11,27,33,45,63,135,165,285,304,345,765,855,964,1144,1575,1744,2134, %T A276504 2295,2805,6424,6604,10725,23584,24244,27645,28875,31174,31354,35445, %U A276504 40755,44164,46672,57046,57057,61444,64005,78975,82095,90195 %N A276504 Numbers n such that phi(n) = phi(n+11), with Euler's totient function phi = A000010. %H A276504 Kevin Ford, <a href="https://arxiv.org/abs/2002.12155">Solutions of phi(n) = phi(n+k) and sigma(n) = sigma(n + k)</a>, arXiv:2002.12155 [math.NT], 2020. %t A276504 Select[Range[150000], EulerPhi[#] == EulerPhi[# + 11] &] %o A276504 (Magma) [n: n in [1..100000] | EulerPhi(n) eq EulerPhi(n+11)]; %Y A276504 Cf. A000010. %Y A276504 Cf. similar sequences listed in A276503. %K A276504 nonn,easy %O A276504 1,1 %A A276504 _Vincenzo Librandi_, Sep 08 2016