A286871 Number of irredundant sets in the n X n king graph.

2, 5, 43, 647, 22049, 1455385, 218691097, 72877697369, 51489351108548, 76986419992442614, 244445556617038272066, 1683765308911934025295376

Offset: 1

Author

Andrew Howroyd, Aug 02 2017

Keywords

• nonn
• more

Links

• Eric Weisstein's World of Mathematics, Irredundant Set
• Eric Weisstein's World of Mathematics, King Graph

Crossrefs

Main diagonal of A286870.

Cf. A075550, A075709.

Programs

Mathematica

A286870 = Import["https://oeis.org/A286870/b286870.txt", "Table"][[All, 2]];
a[n_] := A286870[[2 n^2 - 2 n + 1]];
Table[a[n], {n, 1, 9}] (* Jean-François Alcover, Sep 23 2019 *)

Extensions

a(10)-a(12) from Christian Sievers, Nov 22 2023