

A276031


Number of edges in the graded poset of the partitions of n taken modulo 3, where a partition into k parts is joined to a partition into k+1 parts if the latter is a refinement of the former.


1



0, 1, 2, 5, 9, 14, 21, 30, 41, 54, 70, 89, 110, 135, 164, 195, 231, 272, 315, 364, 419, 476, 540, 611, 684, 765, 854, 945, 1045, 1154, 1265, 1386, 1517, 1650, 1794, 1949, 2106, 2275, 2456, 2639, 2835, 3044, 3255, 3480, 3719, 3960, 4216, 4487, 4760, 5049, 5354
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OFFSET

1,3


LINKS



FORMULA

G.f.: (x^62*x^5+x^4x^3+2*x^2+1)*x^2/((x^2+x+1)^2*(x1)^4).  Alois P. Heinz, Aug 27 2016


EXAMPLE

a(6) = 14, the 14 edges are: (111111)  (21111), (21111)  (1110), (21111)  (2211), (1110)  (111), (1110)  (210), (2211)  (111), (2211)  (210), (2211)  (222), (210)  (00), (210)  (21), (111)  (21), (222)  (21), (00)  (0), (21)  (0).


CROSSREFS



KEYWORD

nonn


AUTHOR



EXTENSIONS



STATUS

approved



