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 A333741 #11 Apr 15 2020 12:31:28
%S A333741 7,635,1015,2695,6497,10307,12317,13445,46205,77693,81303,133787,
%T A333741 134995,151823,162925,180633,181427,220113,288925,359905,392819,
%U A333741 404471,439097,453167,485237,682649,739023,840851,879303,910195,988713,1392317,1410119,1434895,1503347
%N A333741 Odd numbers k such that phi(k) = phi(k+2), where phi is the Euler totient function (A000010).
%C A333741 The odd terms of A001494. These terms are relatively rare: of the first 10000 terms of A001494 only 63 are odd.
%H A333741 Amiram Eldar, <a href="/A333741/b333741.txt">Table of n, a(n) for n = 1..1000</a>
%e A333741 7 is a term since phi(7) = phi(9) = 6.
%t A333741 Select[Range[1, 10^6, 2], EulerPhi[#] == EulerPhi[# + 2] &]
%t A333741 2#-1&/@SequencePosition[EulerPhi[Range[1,151*10^4,2]],{x_,x_}][[All,1]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Apr 15 2020 *)
%Y A333741 Cf. A000010, A001274.
%K A333741 nonn
%O A333741 1,1
%A A333741 _Amiram Eldar_, Apr 03 2020