A356214 Number of edge covers in the n-Sierpinski gasket graph.

4, 198, 31257772, 119663504378704719130518, 6713329439711345431716916679280868301022936622514475069583264989008212

Offset

1,1

Links

Christian Sievers, Table of n, a(n) for n = 1..7

Eric Weisstein's World of Mathematics, Edge Cover.

Eric Weisstein's World of Mathematics, Sierpinski Gasket Graph.

Mathematica

NestList[Table[Sum[#[[1 + Boole[i > 1] + Boole[Mod[xy, 2] == 1] + Boole[Mod[xz, 2] == 1]]] #[[1 + Boole[i > 2] + Boole[Floor[xy/2] == 1] + Boole[Mod[yz, 2] == 1]]] #[[1 + Boole[i > 3] + Boole[Floor[xz/2] == 1] + Boole[Floor[yz/2] == 1]]], {xy, 3}, {xz, 3}, {yz, 3}], {i, 4}] &, {1, 0, 1, 4}, 5][[All, -1]] (* Eric W. Weisstein, Dec 09 2024 *)

Prog

(PARI) a(n)={my(s=[1, 0, 1, 4]); for(k=2, n, s=vector(4, i, sum(xy=1, 3, sum(xz=1, 3, sum(yz=1, 3, s[1+(i>1)+(xy%2)+(xz%2)]*s[1+(i>2)+(xy\2)+(yz%2)]*s[1+(i>3)+(xz\2)+(yz\2)]))))); s[4]} \\ Christian Sievers, Jul 19 2024

Crossrefs

Sequence in context: A065246 A297061 A156235 * A034862 A174776 A216932

Adjacent sequences: A356211 A356212 A356213 * A356215 A356216 A356217

Keyword

nonn

Author

Eric W. Weisstein, Jul 29 2022

Extensions

a(4) and beyond from Christian Sievers, Jul 19 2024

Status

approved