A339121 Number of cycles in the grid graph P_9 X P_n.

36, 4040, 542295, 51139577, 4237530095, 345142437669, 28251882697663, 2318527339461265, 190273063549680295, 15609156135669687673, 1280305089790914190288, 105011610206669201362004, 8613171107463963712000106, 706463610718638922253288622, 57945052730138702492774189915

Offset

2,1

Links

Seiichi Manyama, Table of n, a(n) for n = 2..150

Eric Weisstein's World of Mathematics, Graph Cycle

Eric Weisstein's World of Mathematics, Grid Graph

Prog

(Python)
# Using graphillion
from graphillion import GraphSet
import graphillion.tutorial as tl
def A(n, k):
    universe = tl.grid(n - 1, k - 1)
    GraphSet.set_universe(universe)
    cycles = GraphSet.cycles()
    return cycles.len()
def A339121(n):
    return A(n, 9)
print([A339121(n) for n in range(2, 15)])

Crossrefs

Cf. A140517, A231829.

Sequence in context: A295595 A003744 A163034 * A184270 A187405 A102794

Adjacent sequences: A339118 A339119 A339120 * A339122 A339123 A339124

Keyword

nonn

Author

Seiichi Manyama, Nov 24 2020

Status

approved