A338962 Number of (undirected) paths in C_6 X P_n.

30, 3366, 183684, 8092632, 316544562, 11481159930, 395458712832, 13123275738432, 423525613823934, 13378503050329794, 415551681048983880, 12735329289585862200, 386086186106267296494, 11601553028839397641626, 346091203382132944992240, 10262539815169483791720708

Offset

1,1

Links

Table of n, a(n) for n=1..16.

Prog

(Python)
# Using graphillion
from graphillion import GraphSet
def make_CnXPk(n, k):
    grids = []
    for i in range(1, k + 1):
        for j in range(1, n):
            grids.append((i + (j - 1) * k, i + j * k))
        grids.append((i + (n - 1) * k, i))
    for i in range(1, k * n, k):
        for j in range(1, k):
            grids.append((i + j - 1, i + j))
    return grids
def A(start, goal, n, k):
    universe = make_CnXPk(n, k)
    GraphSet.set_universe(universe)
    paths = GraphSet.paths(start, goal)
    return paths.len()
def B(n, k):
    m = k * n
    s = 0
    for i in range(1, m):
        for j in range(i + 1, m + 1):
            s += A(i, j, n, k)
    return s
def A338962(n):
    return B(6, n)
print([A338962(n) for n in range(1, 6)])

Crossrefs

Cf. A338709, A338960, A338961, A338963.

Sequence in context: A209788 A265855 A289395 * A115465 A152131 A159993

Adjacent sequences: A338959 A338960 A338961 * A338963 A338964 A338965

Keyword

nonn

Author

Seiichi Manyama, Dec 18 2020

Status

approved