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A289709 Number of independent vertex sets and vertex covers in the n-triangular honeycomb queen graph. 5
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)

CROSSREFS

Cf. A193986, A283117, A289883, A289893, A326611.

Sequence in context: A202135 A068875 A262543 * A192574 A135336 A149825

Adjacent sequences:  A289706 A289707 A289708 * A289710 A289711 A289712

KEYWORD

nonn,more

AUTHOR

Eric W. Weisstein, Jul 14 2017

EXTENSIONS

a(13)-a(21) from Andrew Howroyd, Sep 12 2019

STATUS

approved

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Last modified October 14 07:31 EDT 2019. Contains 327995 sequences. (Running on oeis4.)