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 A008331 #18 Jun 20 2023 10:02:49 %S A008331 2,2,2,4,4,6,6,8,8,8,16,18,12,20,16,18,16,30,32,24,36,32,24,24,42,32, %T A008331 48,36,40,36,64,40,44,48,40,72,78,80,48,56,48,72,64,96,60,80,104,96, %U A008331 72,88,72,64,110,72,84,80,72,128,138,92,140,84,120,96,156,104,164,156,112,120,116 %N A008331 a(n) = phi(prime(n)+1). %H A008331 Michael De Vlieger, <a href="/A008331/b008331.txt">Table of n, a(n) for n = 1..10000</a> %F A008331 a(n) = A000010(A008864(n)). - _Michel Marcus_, Feb 17 2021 %p A008331 for i from 1 to 500 do if isprime(i) then print(phi(i+1)); fi; od; %t A008331 EulerPhi[1 + Prime@ Range@ 71] (* _Michael De Vlieger_, Feb 17 2021 *) %o A008331 (PARI) a(n) = eulerphi(prime(n)+1); \\ _Michel Marcus_, Feb 17 2021 %Y A008331 Cf. A000010, A008864, A363700. %K A008331 nonn %O A008331 1,1 %A A008331 _N. J. A. Sloane_ %E A008331 Offset 1 from _Michel Marcus_, Feb 17 2021