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A334004 Number of spanning trees in the graph P_9 x P_n. 3
1, 40545, 750331584, 11905151192865, 179796299139278305, 2662079368040434932480, 39067130344394503972142977, 570929651486775190858844600865, 8326627661691818545121844900397056, 121316352059447360262303173959408358625, 1766658737971934774798769007686932254154689 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Seiichi Manyama, Table of n, a(n) for n = 1..200

MATHEMATICA

a[n_] := Resultant[ChebyshevU[n - 1, x/2], ChebyshevU[8, (4 - x)/2], x]; Array[a, 11] (* Amiram Eldar, May 04 2021 *)

PROG

(PARI) {a(n) = polresultant(polchebyshev(n-1, 2, x/2), polchebyshev(8, 2, (4-x)/2))}

(Python)

# Using graphillion

from graphillion import GraphSet

import graphillion.tutorial as tl

def A116469(n, k):

    if n == 1 or k == 1: return 1

    universe = tl.grid(n - 1, k - 1)

    GraphSet.set_universe(universe)

    spanning_trees = GraphSet.trees(is_spanning=True)

    return spanning_trees.len()

def A334004(n):

    return A116469(n, 9)

print([A334004(n) for n in range(1, 10)])

CROSSREFS

Row m=9 of A116469.

Sequence in context: A218399 A090060 A250955 * A097238 A249879 A046180

Adjacent sequences:  A334001 A334002 A334003 * A334005 A334006 A334007

KEYWORD

nonn

AUTHOR

Seiichi Manyama, Apr 12 2020

STATUS

approved

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Last modified May 20 23:05 EDT 2022. Contains 353886 sequences. (Running on oeis4.)