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A071077 Number of permutations that avoid the generalized pattern 1234-5. 4
1, 1, 2, 6, 24, 119, 705, 4857, 38142, 336291, 3289057, 35337067, 413698248, 5241768017, 71465060725, 1043175024243, 16231998346794, 268207096127991, 4690005160446721, 86528908665043683, 1679764981327051508, 34226671269330933413, 730361830628447403029 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

REFERENCES

S. Kitaev, Partially Ordered Generalized Patterns, Discrete Math. 298 (2005), no. 1-3, 212-229.

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..450

S. Kitaev, Partially Ordered Generalized Patterns

FORMULA

E.g.f.: exp(int(A(y), y=0..x)), where A(y) = 1/(Sum_{i>=0} y^{4*i}/(4*i)! - Sum_{i>=0} y^{4*i+1}/(4*i+1)!).

MAPLE

b:= proc(u, o, t) option remember; `if`(u+o=0, 1, add(

      `if`(t=2 and o>j, 0, b(u+j-1, o-j, t+1)), j=1..o)+

       add(b(u-j, o+j-1, 0), j=1..u))

    end:

a:= n-> b(n, 0$2):

seq(a(n), n=0..25);  # Alois P. Heinz, Nov 14 2015

CROSSREFS

Cf. A071088, A071075, A071076.

Sequence in context: A264432 A094198 A297200 * A202213 A202216 A202217

Adjacent sequences:  A071074 A071075 A071076 * A071078 A071079 A071080

KEYWORD

nonn

AUTHOR

Sergey Kitaev (kitaev(AT)math.chalmers.se), May 26 2002

EXTENSIONS

Corrected and extended by Vladeta Jovovic, May 28 2002

STATUS

approved

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Last modified October 15 15:03 EDT 2019. Contains 328030 sequences. (Running on oeis4.)