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!)
A293971 Number of sets of exactly nine nonempty words with a total of n letters over n-ary alphabet such that within each prefix of a word every letter of the alphabet is at least as frequent as the subsequent alphabet letter. 2
45, 740, 7265, 54844, 355786, 2086218, 11402599, 59244154, 296592681, 1444795518, 6898985716, 32478508414, 151439118998, 702039301562, 3246061184641, 15011635714770, 69604533115983, 324297338323040, 1521325113273431, 7199243859471728, 34426802099939524 (list; graph; refs; listen; history; text; internal format)
OFFSET

25,1

LINKS

Alois P. Heinz, Table of n, a(n) for n = 25..820

FORMULA

a(n) = [x^n y^9] Product_{j>=1} (1+y*x^j)^A000085(j).

MAPLE

g:= proc(n) option remember; `if`(n<2, 1, g(n-1)+(n-1)*g(n-2)) end:

b:= proc(n, i) option remember; series(`if`(n=0, 1, `if`(i<1, 0,

      add(b(n-i*j, i-1)*binomial(g(i), j)*x^j, j=0..n/i))), x, 10)

    end:

a:= n-> coeff(b(n$2), x, 9):

seq(a(n), n=25..49);

CROSSREFS

Column k=9 of A293815.

Cf. A000085.

Sequence in context: A105251 A099632 A264138 * A341427 A024379 A134290

Adjacent sequences:  A293968 A293969 A293970 * A293972 A293973 A293974

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Oct 20 2017

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 January 27 14:44 EST 2022. Contains 350607 sequences. (Running on oeis4.)