login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A243676 Number of hypoplactic classes of 4-parking functions of length n. 0
1, 9, 113, 1649, 26225 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

See Novelli-Thibon (2014) for precise definition.

LINKS

Table of n, a(n) for n=1..5.

J.-C. Novelli, J.-Y. Thibon, Hopf Algebras of m-permutations,(m+1)-ary trees, and m-parking functions, arXiv preprint arXiv:1403.5962 [math.CO], 2014. See Fig. 23.

FORMULA

a(n+1) = Sum_{i=0..n} Sum_{j=0..i} (-2)^(n-i)*binomial(i,j)*binomial(4*i+j, n)*binomial(n+1,i)/(n+1) (conjectured). - Michael D. Weiner, May 25 2017

a(n) = Sum_{i=1..n} binomial(4*n, i-1)*binomial(n, i)*2^(i-1)/n (conjectured). - Michael D. Weiner, Jul 24 2019

CROSSREFS

Sequence in context: A156949 A155624 A165224 * A012116 A157551 A157570

Adjacent sequences:  A243673 A243674 A243675 * A243677 A243678 A243679

KEYWORD

nonn,more

AUTHOR

N. J. A. Sloane, Jun 14 2014

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 23 00:24 EDT 2020. Contains 337962 sequences. (Running on oeis4.)