A101900 - OEIS

A101900

Column 0 of triangular matrix A101897, in which column k equals column 0 of A101897^(k+1) and where the n-th row sums are zero for n>0.

1, -1, 1, -2, 5, -17, 71, -357, 2101, -14203, 108609, -927961, 8769087, -90874197, 1025292311, -12516360103, 164433702745, -2313858448075, 34730232119381, -553983478001961, 9359820238735507, -167004393073794933, 3138414712193291915, -61966152586833353847

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OFFSET

0,4

COMMENTS

|a(n)| is the number of n-length permutations avoiding the dotted pattern 23\dot{1}(conjectured). - Michael D. Weiner, Jul 26 2018

LINKS

Table of n, a(n) for n=0..23.

Isak Hilmarsson, Ingibjorg Jonsdottir, Steinunn Sigurdardottir and Sigridur Vidarsdottir, Wilf-classification of mesh patterns of short length, Reykjavík University, Thesis, May 2011.

Isak Hilmarsson, Ingibjorg Jonsdottir, Steinunn Sigurdardottir and Sigridur Vidarsdottir, Wilf-classification of mesh patterns of short length, The Electronic Journal of Combinatorics, Volume 22, Issue 4 (2015).

CROSSREFS

Cf. A101897, A101898, A101899, A101901.

Sequence in context: A143382 A057219 A084869 * A005966 A336282 A082282

Adjacent sequences: A101897 A101898 A101899 * A101901 A101902 A101903

KEYWORD

sign

AUTHOR

Paul D. Hanna, Dec 20 2004

STATUS

approved