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 A002638 M0913 N0345 #39 Dec 27 2024 22:37:42
%S A002638 -1,1,2,3,12,52,456,6873,191532,9733032,903753248,154108311046,
%T A002638 48542114686912,28401423719121392,31021002160355166800,
%U A002638 63530415842308265086523,244912778438520759443245824,1783398846284777975419599903948,24605641171260376770598003978281472
%N A002638 a(n) = (number of nonisomorphic nontransitive prime tournaments on n nodes) - Moebius(n).
%D A002638 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
%D A002638 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H A002638 Pontus von Brömssen, <a href="/A002638/b002638.txt">Table of n, a(n) for n = 1..76</a>
%H A002638 J. W. Moon and M. Goldberg, <a href="http://projecteuclid.org/euclid.dmj/1077378978">On the composition of two tournaments</a>, Duke Mathematical Journal, vol.37, no.2 (1970), pp.323-332. (subscription required)
%H A002638 J. W. Moon and M. Goldberg, <a href="/A000568/a000568_2.pdf">On the composition of two tournaments</a>, Duke Mathematical Journal 37.2 (1970): 323-332. [Annotated scans of pages 331 and 332 only]
%H A002638 <a href="/index/To#tournament">Index entries for sequences related to tournaments</a>
%F A002638 a(1) = -1, a(n) = A000568(n) - Sum_{d|n, d!=1, d!=n} a(d) * A000568(n / d). - _Sean A. Irvine_, Oct 19 2015
%F A002638 a(n) = A259106(n) - A008683(n). - _Pontus von Brömssen_, Oct 03 2020
%Y A002638 Cf. A000568, A008683, A259106.
%K A002638 sign
%O A002638 1,3
%A A002638 _N. J. A. Sloane_
%E A002638 Definition clarified by _N. J. A. Sloane_, Jun 23 2015
%E A002638 More terms from _Sean A. Irvine_, Oct 19 2015
%E A002638 a(19) from _Pontus von Brömssen_, Oct 03 2020