A289709 - OEIS

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A289709

Number of independent vertex sets and vertex covers in the n-triangular honeycomb queen graph.

2, 4, 10, 28, 84, 272, 946, 3486, 13560, 55432, 236852, 1054928, 4881972, 23420436, 116204016, 595246848, 3142169416, 17068245184, 95267426432, 545732236936, 3204607199704

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Table of n, a(n) for n=1..21.

Eric Weisstein's World of Mathematics, Independent Vertex Set

Eric Weisstein's World of Mathematics, Vertex Cover

FORMULA

From Andrew Howroyd, Sep 12 2019: (Start)

a(n) = 6*A283117(n) - 2*A326611(n) - 3*2^ceiling(n/2).

a(n) = 1 + Sum_{k>=1} A193986(n,k).

(End)