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A174706
The number of permutations p of {1,...,n} such that |p(i)-p(i+1)| is in {3,4} for all i from 1 to n-1.
13
1, 0, 0, 0, 0, 2, 14, 12, 0, 0, 0, 0, 30, 104, 112, 48, 40, 48, 112, 400, 964, 1276, 1202, 1280, 1714, 3004, 6120, 11472, 16730, 20884, 26308, 36676, 57570, 96642, 158864, 237592, 330064, 453476, 647862, 975210, 1515766, 2345634, 3505078, 5064148, 7241688
OFFSET
1,6
COMMENTS
For n>1, a(n)/2 is the number of Hamiltonian paths on the graph with vertex set {1,...,n} where i is adjacent to j iff |i-j| is in {3,4}.
LINKS
KEYWORD
nonn
AUTHOR
W. Edwin Clark, Mar 27 2010
EXTENSIONS
a(28)-a(38) from Robert Gerbicz, Nov 27 2010
a(39)-a(45) from Andrew Howroyd, Apr 05 2016
STATUS
approved