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A226440
Number of permutations of {1..n} with fewer than 7 interior elements having values lying between the values of their neighbors.
1
1, 1, 2, 6, 24, 120, 720, 5040, 40320, 362878, 3627778, 39830282, 475089392, 6094561180, 83333937940, 1205398303180, 18331873363480, 291706615484450, 4838414115229430, 83404373736108502, 1490681666580459304, 27572241018065482032, 526959942343051879032
OFFSET
0,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..480 (terms n = 1..206 from R. H. Hardin)
EXAMPLE
Some solutions for n=7
..2....2....2....1....7....2....6....4....2....2....7....1....1....4....6....4
..5....3....1....7....4....3....7....2....1....7....3....3....5....3....3....5
..3....7....6....2....5....6....2....1....5....6....5....4....4....2....2....6
..4....1....4....4....2....7....1....5....6....4....6....6....7....1....4....2
..7....4....3....3....3....4....4....3....4....5....2....7....3....5....7....3
..1....6....5....5....6....1....5....6....3....3....1....2....2....6....1....7
..6....5....7....6....1....5....3....7....7....1....4....5....6....7....5....1
CROSSREFS
Column 7 of A226441.
Sequence in context: A054873 A324075 A193936 * A248841 A072132 A230231
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jun 06 2013
EXTENSIONS
a(0)=1 prepended by Alois P. Heinz, Jul 17 2024
STATUS
approved