A056392 Number of step shifted (decimated) sequence structures using a maximum of three different symbols.

1, 2, 4, 10, 14, 70, 68, 332, 577, 2510, 2980, 23372, 22218, 133150, 300964, 909382, 1345634, 10767202, 10762820, 72957100, 145362932, 523029526, 713213956, 5893709440, 7060765733, 35303782550

Offset

1,2

Comments

See A056371 for an explanation of step shifts. Permuting the symbols will not change the structure.

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]

Links

Table of n, a(n) for n=1..26.

Formula

Use de Bruijn's generalization of Polya's enumeration theorem as discussed in reference.

a(n) = Sum_{k=1..3} A288620(n, k). - Andrew Howroyd, Jun 13 2017

Crossrefs

Cf. A056372, A288620.

Sequence in context: A236547 A078775 A351160 * A080149 A217134 A351927

Adjacent sequences: A056389 A056390 A056391 * A056393 A056394 A056395

Keyword

nonn

Author

Marks R. Nester

Status

approved