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 A055929 #17 Jun 03 2024 03:47:48 %S A055929 1,2,32,1152,8294400,1194393600,64210599936000,20804234379264000, %T A055929 4229084764616785920000,1396531754239566739931136000000, %U A055929 1256878578815610065938022400000000,2046959290878571310305421983481856000000000,4853749870531268290996216607232176947200000000000 %N A055929 Euler totient function of the factorial of prime(n). %H A055929 Amiram Eldar, <a href="/A055929/b055929.txt">Table of n, a(n) for n = 1..87</a> %F A055929 a(n) = phi(prime(n)!) = A000010(A039716(n)) = A048855(prime(n)). %t A055929 a[n_] := EulerPhi[Prime[n]!]; Array[a, 12] (* _Amiram Eldar_, Jun 03 2024 *) %o A055929 (PARI) a(n) = eulerphi(prime(n)!); \\ _Amiram Eldar_, Jun 03 2024 %Y A055929 Cf. A000010, A000142, A039716, A048855. %K A055929 nonn %O A055929 1,2 %A A055929 _Labos Elemer_, Jul 17 2000 %E A055929 a(12)-a(13) from _Amiram Eldar_, Jun 03 2024