A005368 Occurrences of principal character.

1, 0, 1, 3, 6, 15, 42, 109, 320, 979, 3137, 10603, 37728, 140423, 546859, 2220294, 9374309, 41059926, 186149869, 871717073, 4208841555, 20917405824, 106849492793

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• more

References

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

Links

• Russell Merris and William Watkins, Tensors and graphs, SIAM J. Algebraic Discrete Methods 4 (1983), no. 4, 534-547.

Crossrefs

Cf. A259976.

Possibly first differences of A000664 or, equivalently, row n = 2 of A331509.

Extensions

a(7)-a(17) from Andrey Zabolotskiy, Sep 10 2018

a(18)-a(22) from Sean A. Irvine, Mar 02 2022