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 A067798 #19 May 15 2016 16:33:40
%S A067798 1,2,3,5,9,15,21,35,39,45,75,99,135,231,255,363,483,765,855,1295,1599,
%T A067798 2015,2115,4335,6783,9999,14399,16095,16599,18495,30495,53823,62799,
%U A067798 63455,65535,77615,155319,186999,196095,327675,589815,686735,722015
%N A067798 Numbers n such that phi(n)+phi(n+1)=n+1.
%H A067798 Giovanni Resta, <a href="/A067798/b067798.txt">Table of n, a(n) for n = 1..76</a>
%F A067798 {n: A000010(n) = A051953(n+1)}. - _Omar E. Pol_, May 15 2016
%t A067798 Select[Range[10^5], Plus @@ EulerPhi[{#, # + 1}] == # + 1 &] (* _Giovanni Resta_, May 15 2016 *)
%o A067798 (PARI) isok(n) = eulerphi(n)+eulerphi(n+1) == n+1; \\ _Michel Marcus_, May 15 2016
%Y A067798 Cf. A000010, A051953, A067796.
%K A067798 nonn
%O A067798 1,2
%A A067798 _Benoit Cloitre_, Feb 07 2002
%E A067798 More terms from _Dean Hickerson_, Feb 16 2002