1,2

The layer sequence is the sequence of the cardinalities of the layers accumulating around a (finite-sided) polygon of the tessellation under successive side-reflections.

Illustration

G.f.: (1+x)^2/(x^2-3*x+1)

{a(n)/5} for n>1 is A001906.

Sequence in context: A132985 A022570 A000333 this_sequence A038066 A113861 A080870

Adjacent sequences: A054885 A054886 A054887 this_sequence A054889 A054890 A054891

nonn

Paolo Dominici (pl.dm(AT)libero.it), May 23 2000