login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A189585 Number of permutations of 1..n with displacements restricted to {-4,-3,-1,0,2}. 1
1, 1, 2, 4, 10, 20, 37, 72, 140, 277, 553, 1085, 2129, 4185, 8228, 16208, 31902, 62747, 123449, 242860, 477830, 940205, 1849830, 3639492, 7160647, 14088415, 27719015, 54537120, 107301253, 211114467, 415365925, 817229415, 1607893843, 3163519669 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

FORMULA

Empirical: a(n) = a(n-1) +2*a(n-3) +a(n-4) +4*a(n-5) +2*a(n-6) +a(n-8) -4*a(n-9) -2*a(n-10) -a(n-11) -a(n-12) +a(n-15).

Empirical g.f.: x*(1 + x^2 + 3*x^4 + x^5 + x^6 + x^7 - 3*x^8 - 2*x^9 - x^10 - x^11 + x^14) / (1 - x - 2*x^3 - x^4 - 4*x^5 - 2*x^6 - x^8 + 4*x^9 + 2*x^10 + x^11 + x^12 - x^15). - Colin Barker, May 02 2018

EXAMPLE

Some solutions for n=11:

..4....1....1....1....2....1....4....5....1....2....1....1....4....4....1....1

..3....2....2....5....3....6....2....6....5....3....2....2....2....6....5....2

..1....3....3....4....1....3....1....1....3....1....7....7....1....1....4....4

..2....5....4....2....4....2....5....2....2....5....5....5....8....2....2....8

..5....6....8....3....5....9....3....3....6....6....3....3....3....3....3....3

..6....4....6....6....6....4...10....4....4....4....4....4....6...10....7....7

.10....8....5....7....8....5...11....7...10....8...11...10....5....5...11....5

..9....9....9....9...11....8....6...11....8...11....6....6...11....9....6....6

..7....7....7...10....7....7....7...10....7....7...10....9....7....7...10...10

..8...10...10....8...10...10....8....8...11...10....8....8...10....8....8...11

.11...11...11...11....9...11....9....9....9....9....9...11....9...11....9....9

CROSSREFS

Sequence in context: A236001 A258092 A263993 * A239346 A004647 A265096

Adjacent sequences: A189582 A189583 A189584 * A189586 A189587 A189588

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 24 2011

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified February 1 08:17 EST 2023. Contains 359984 sequences. (Running on oeis4.)