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

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: A068875 A262543 A348197 * 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