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 A067797 #16 Jun 08 2022 03:19:57 %S A067797 4,6,8,50,74,110,170,174,890,902,1310,1434,1826,2714,4190,5030,6494, %T A067797 8234,8474,10142,14390,31670,32394,40514,89990,95174,101834,102554, %U A067797 135374,151754,173942,206054,248394,259694,288266,330614,516242,650654,780554,913994,941714 %N A067797 Numbers k such that phi(k) + phi(k+1) = k+2. %H A067797 Amiram Eldar, <a href="/A067797/b067797.txt">Table of n, a(n) for n = 1..72</a> %t A067797 Select[Range[10^6],EulerPhi[#]+EulerPhi[#+1]==#+2&] (* _Harvey P. Dale_, Apr 04 2019 *) %o A067797 (PARI) isok(n) = eulerphi(n) + eulerphi(n+1) == n+2; \\ _Michel Marcus_, Nov 23 2013 %Y A067797 Cf. A000010, A092404. %K A067797 nonn %O A067797 1,1 %A A067797 _Benoit Cloitre_, Feb 07 2002 %E A067797 More terms from _Michel Marcus_, Nov 23 2013