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 A038780 #23 May 02 2024 14:44:02
%S A038780 9,36,196,11664,123904,16941456,213218404,36384036516,91921690256400,
%T A038780 1281107924034624,3643830108147610000,755580082985683928064,
%U A038780 10965324181121364597904,2340151860941299402849476,7500891349210337560308603456,24695823438181435496869784039184
%N A038780 An intermediate sequence for counting nonisomorphic circulant directed p^2-graphs, indexed by odd primes p.
%H A038780 M. Klin, V. A. Liskovets and R. Poeschel, <a href="http://www.mat.univie.ac.at/~slc/wpapers/s36klp.html">Analytical enumeration of circulant graphs with prime-squared vertices</a>, Sem. Lotharingien de Combin., B36d, 1996, 36 pages.
%F A038780 a(n) = A049297(prime(n+1))^2.
%F A038780 a(n) = ( (1/(p-1)) * Sum_{r|p-1} phi(r) * 2^((p-1)/r) )^2 where p = prime(n+1). - _Sean A. Irvine_, Feb 14 2021
%o A038780 (PARI) a(n) = my(p=prime(n+1)); (((1/(p-1)) * sumdiv(p-1,r, eulerphi(r) * 2^((p-1)/r)))^2); \\ _Sean A. Irvine_, Feb 14 2021
%Y A038780 Cf. A038777, A038779.
%K A038780 nonn,easy
%O A038780 1,1
%A A038780 _N. J. A. Sloane_, May 04 2000
%E A038780 More terms from _Valery A. Liskovets_, May 09 2001
%E A038780 More terms from _Sean A. Irvine_, Feb 14 2021