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 A092790 #21 May 12 2025 08:29:51
%S A092790 2,5,6,14,8,27,20,33,24,65,28,90,48,68,72,152,60,189,88,138,120,275,
%T A092790 104,270,168,261,180,434,128,495,272,350,288,444,228,702,360,492,336,
%U A092790 860,264,945,460,564,528,1127,400,1071,520,848,648,1430,504,1140,696,1062,840,1769
%N A092790 a(n) = (n+1)*phi(n-1)/2.
%C A092790 [The old entry with this sequence number was a duplicate of A082470.]
%C A092790 Prepending [0, 3] and setting offset = 0 the sequence becomes the row sums of A378068. - _Peter Luschny_, Dec 27 2024
%C A092790 a(n) is the sum of row n-1 of A078401. - _Amiram Eldar_, May 12 2025
%H A092790 Amiram Eldar, <a href="/A092790/b092790.txt">Table of n, a(n) for n = 3..10000</a>
%H A092790 Jeffrey Jaffe, <a href="http://www.jstor.org/stable/2689434">Permutation numbers</a>, Math. Mag., 49 (1976), 80-84.
%t A092790 Table[(n+1) EulerPhi[n-1]/2,{n,3,60}] (* _Harvey P. Dale_, Apr 22 2012 *)
%o A092790 (PARI) a(n) = (n+1)*eulerphi(n-1)/2; \\ _Michel Marcus_, Sep 18 2017
%Y A092790 Cf. A000010 (phi), A078401, A378068.
%K A092790 nonn,easy
%O A092790 3,1
%A A092790 _N. J. A. Sloane_, Nov 04 2008