login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A243484 Number of isoscent sequences of length n with maximal number of descents. 2
1, 1, 2, 1, 6, 2, 28, 10, 1, 98, 22, 2, 570, 130, 17, 1, 1842, 337, 38, 2, 13104, 2437, 318, 26, 1, 45188, 7126, 805, 58, 2, 387323, 61504, 7496, 658, 37, 1, 1422382, 196200, 20978, 1631, 82, 2, 14272601, 1971561, 220497, 19175, 1216, 50, 1, 54989728, 6713935 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Joerg Arndt and Alois P. Heinz, Table of n, a(n) for n = 0..100

FORMULA

a(n) = A242352(n,n+2-ceiling(2*sqrt(n+1))).

MATHEMATICA

b[n_, i_, t_] := b[n, i, t] = If[n<1, 1, Expand[ Sum[If[j<i, x, 1]*b[n-1, j, t + If[j == i, 1, 0]], {j, 0, t+1}]]]; a[n_] := Coefficient[b[n-1, 0, 0], x, n + 2 - Ceiling[2*Sqrt[n+1]]]; Table[a[n], {n, 0, 50}] (* Jean-Fran├žois Alcover, Feb 09 2015, after A242352 *)

CROSSREFS

Sequence in context: A185330 A217955 A284434 * A181811 A284431 A006019

Adjacent sequences:  A243481 A243482 A243483 * A243485 A243486 A243487

KEYWORD

nonn

AUTHOR

Joerg Arndt and Alois P. Heinz, Jun 05 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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 15 21:06 EDT 2018. Contains 316237 sequences. (Running on oeis4.)