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Occurrences of principal character.
(Formerly M2589)
2

%I M2589 #26 Mar 02 2022 20:59:39

%S 1,0,1,3,6,15,42,109,320,979,3137,10603,37728,140423,546859,2220294,

%T 9374309,41059926,186149869,871717073,4208841555,20917405824,

%U 106849492793

%N Occurrences of principal character.

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%H Russell Merris and William Watkins, <a href="https://doi.org/10.1137/0604054">Tensors and graphs</a>, SIAM J. Algebraic Discrete Methods 4 (1983), no. 4, 534-547.

%Y Cf. A259976.

%Y Possibly row n = 2 of A331509.

%K nonn,more

%O 0,4

%A _N. J. A. Sloane_

%E a(7)-a(17) from _Andrey Zabolotskiy_, Sep 10 2018

%E a(18)-a(22) from _Sean A. Irvine_, Mar 02 2022