A056282 Number of primitive (aperiodic) word structures of length n which contain exactly six different symbols.
0, 0, 0, 0, 0, 1, 21, 266, 2646, 22827, 179487, 1323651, 9321312, 63436352, 420693273, 2734926292, 17505749898, 110687248392, 693081601779, 4306078872557, 26585679462783, 163305339165738, 998969857983405
Offset: 1
Keywords
References
- M. R. Nester (1999). Mathematical investigations of some plant interaction designs. PhD Thesis. University of Queensland, Brisbane, Australia. [See A056391 for pdf file of Chap. 2]
Formula
a(n) = Sum_{n > 0, d|n} mu(d)*A000770(n/d).
G.f.: Sum_{k>=1} mu(k) * x^(6*k) / Product_{j=1..6} (1 - j*x^k). - Ilya Gutkovskiy, Apr 15 2021
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