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 A339202 Number of (undirected) Hamiltonian cycles on the n X 5 king graph. 4
 16, 744, 50354, 2462064, 139472532, 7621612496, 420570135944, 23122750594160, 1272913614363472, 70046421764651488, 3855022666171830728, 212153410644220498768, 11675594777180367650512, 642548778638303396036528, 35361754611803652243506632, 1946082778374581215370587632 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,1 LINKS Seiichi Manyama, Table of n, a(n) for n = 2..400 Vaclav Kotesovec, Empirical g.f. Eric Weisstein's World of Mathematics, Hamiltonian Cycle Eric Weisstein's World of Mathematics, King Graph PROG (Python) # Using graphillion from graphillion import GraphSet def make_nXk_king_graph(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))             if i < k:                 grids.append((i + (j - 1) * k, i + j * k + 1))             if i > 1:                 grids.append((i + (j - 1) * k, i + j * k - 1))     for i in range(1, k * n, k):         for j in range(1, k):             grids.append((i + j - 1, i + j))     return grids def A339190(n, k):     universe = make_nXk_king_graph(n, k)     GraphSet.set_universe(universe)     cycles = GraphSet.cycles(is_hamilton=True)     return cycles.len() def A339202(n):     return A339190(n, 5) print([A339202(n) for n in range(2, 20)]) CROSSREFS Column 5 of A339190. Cf. A339199. Sequence in context: A209537 A086701 A218297 * A307923 A159375 A221527 Adjacent sequences:  A339199 A339200 A339201 * A339203 A339204 A339205 KEYWORD nonn AUTHOR Seiichi Manyama, Nov 27 2020 STATUS approved

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Last modified June 22 15:13 EDT 2021. Contains 345383 sequences. (Running on oeis4.)