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A226438
Number of permutations of {1..n} with fewer than 5 interior elements having values lying between the values of their neighbors.
1
1, 1, 2, 6, 24, 120, 720, 5038, 40066, 353556, 3399246, 35142546, 387129588, 4515261680, 55502974820, 716557285110, 9689420220510, 136922907564972, 2018121531850482, 30972340185946810, 494190208052390752, 8186609585709287112, 140620153367124829272
OFFSET
0,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..481 (terms n = 1..210 from R. H. Hardin)
EXAMPLE
Some solutions for n=7
..3....1....7....3....6....5....6....4....6....4....1....1....4....3....2....5
..4....5....6....2....3....4....5....5....2....1....6....2....7....6....4....6
..7....3....5....4....5....7....2....2....1....7....3....7....2....1....6....1
..2....2....2....6....1....6....3....6....4....5....5....5....1....7....5....7
..5....4....4....1....2....3....7....3....3....2....4....4....6....5....3....2
..6....7....3....5....7....1....1....7....5....6....7....3....3....2....7....3
..1....6....1....7....4....2....4....1....7....3....2....6....5....4....1....4
CROSSREFS
Column 5 of A226441.
Sequence in context: A193935 A177534 A164873 * A248839 A052399 A177553
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jun 06 2013
EXTENSIONS
a(0)=1 prepended by Alois P. Heinz, Jul 17 2024
STATUS
approved