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!)
A134980 a(n) = Sum_{k=0..n} binomial(n,k)*n^(n-k)*A000110(k). 8
1, 2, 10, 77, 799, 10427, 163967, 3017562, 63625324, 1512354975, 40012800675, 1166271373797, 37134022033885, 1282405154139046, 47745103281852282, 1906411492286148245, 81267367663098939459, 3683790958912910588623, 176937226305157687076779 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Main diagonal of array "The first r-Bell numbers", p.3 of Mezo, A108087. - Jonathan Vos Post, Sep 25 2009

Number of partitions of [2n] where at least n blocks contain their own index element.  a(2) = 10: 134|2, 13|24, 13|2|4, 14|23, 1|234, 1|23|4, 14|2|3, 1|24|3, 1|2|34, 1|2|3|4. - Alois P. Heinz, Jan 07 2022

LINKS

Robert Israel, Table of n, a(n) for n = 0..385

R. Jakimczuk, Successive Derivatives and Integer Sequences, J. Int. Seq. 14 (2011) # 11.7.3.

Istvan Mezo, The r-Bell numbers, arXiv:0909.4417 [math.CO], 2009-2010.

I. Mezo, The r-Bell numbers, J. Int. Seq. 14 (2011) # 11.1.1.

FORMULA

a(n) = exp(-1)*Sum_{k>=0} (n+k)^n/k!.

E.g.f.: A(x) = exp(-1)*Sum_{k>=0} (1+k*x)^k/k!.

a(n) = Sum_{k=0..n} Stirling1(n,k)*A000110(n+k). - Vladeta Jovovic, Nov 08 2009

a(n) = n! * [x^n] exp(exp(x) + n*x - 1). - Ilya Gutkovskiy, Sep 26 2017

a(n) ~ exp(exp(1) - 1) * n^n. - Vaclav Kotesovec, Jun 09 2020

MAPLE

with(combinat): a:= n-> add(binomial(n, k)*n^(n-k)*bell(k), k=0..n):

seq(a(n), n=0..20); # Emeric Deutsch, Mar 02 2008

# Alternate:

g:= proc(n) local S;

  S:= series(exp(exp(x)+n*x-1), x, n+1);

n!*coeff(S, x, n);

end proc:

map(g, [$0..30]); # Robert Israel, Sep 29 2017

# third Maple program:

b:= proc(n, k) option remember; `if`(n=0, 1,

      k*b(n-1, k)+ b(n-1, k+1))

    end:

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

seq(a(n), n=0..20);  # Alois P. Heinz, Aug 04 2021

MATHEMATICA

a[n_] := n!*SeriesCoefficient[Exp[Exp[x] + n*x - 1], {x, 0, n}]; Array[a, 19, 0] (* Jean-Fran├žois Alcover, Sep 28 2017, after Ilya Gutkovskiy *)

Join[{1}, Table[Sum[Binomial[n, k]*n^(n-k)*BellB[k], {k, 0, n}], {n, 1, 20}]] (* Vaclav Kotesovec, Jun 09 2020 *)

PROG

(Sage)

def A134980(n):

    return add(binomial(n, k)*n^(n-k)*bell_number(k) for k in (0..n))

[A134980(n) for n in (0..18)]  # Peter Luschny, May 05 2013

CROSSREFS

Main diagonal of A108087.

Cf. A000110.

Sequence in context: A245307 A292632 A095789 * A355471 A240599 A212381

Adjacent sequences:  A134977 A134978 A134979 * A134981 A134982 A134983

KEYWORD

easy,nonn

AUTHOR

Vladeta Jovovic, Feb 04 2008

EXTENSIONS

More terms from Emeric Deutsch, Mar 02 2008

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 5 05:10 EDT 2022. Contains 355087 sequences. (Running on oeis4.)