OFFSET
0,2
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..500
FORMULA
Conjecture: a(n)= 85*a(n-1) -1932*a(n-2) +20403*a(n-3) -116734*a(n-4) +386724*a(n-5) -815141*a(n-6) +1251439*a(n-7) -1690670*a(n-8) +2681994*a(n-9) -4008954*a(n-10) +3390877*a(n-11) -1036420*a(n-12) -178842*a(n-13) +92790*a(n-14) +17732*a(n-15) -5972*a(n-16) +1728*a(n-17) +144*a(n-18). - R. J. Mathar, Mar 13 2023
PROG
(Python)
# Using graphillion
from graphillion import GraphSet
import graphillion.tutorial as tl
def A271592(n, k):
if k == 1: return 1
universe = tl.grid(k - 1, n - 1)
GraphSet.set_universe(universe)
start, goal = 1, n
paths = GraphSet.paths(start, goal, is_hamilton=True)
return paths.len()
def A333603(n):
return A271592(7, 2 * n + 1)
print([A333603(n) for n in range(20)])
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Mar 28 2020
STATUS
approved