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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A255927 a(n) = (3/4) * Sum_{k>=0} (3*k)^n/4^k. 1
1, 1, 5, 33, 285, 3081, 40005, 606033, 10491885, 204343641, 4422082005, 105265315233, 2733583519485, 76902684021801, 2329889536156005, 75629701786875633, 2618654297178083085, 96336948993312237561, 3752590641305604502005, 154294551397830418471233, 6677999524135208461382685 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..400

P. Blasiak, K. A. Penson and A. I. Solomon, Dobinski-type relations and the Log-normal distribution, arXiv:quant-ph/0303030, 2003.

P. Blasiak, K. A. Penson and A. I. Solomon, Dobinski-type relations and the Log-normal distribution, J. Phys. A: Math. Gen. 36, (2003), L273.

Eric Weisstein's MathWorld, Lerch Transcendent

FORMULA

a(n) = Sum_{k>=0} Stirling2(n,k)*k!*3^(n-k).

E.g.f.: 3/(4-exp(3*x)).

Special values of the generalized hypergeometric function n_F_(n-1):

a(n) = (3^(n+1)/16) * hypergeom([2,2,..2],[1,1,..1],1/4), where the sequence in the first square bracket ("upper" parameters) has n elements all equal to 2 whereas the sequence in the second square bracket ("lower" parameters) has n-1 elements all equal to 1.

Example: a(5) = 729 * hypergeom([2,2,2,2,2],[1,1,1,1],1/4)/16 = 3081.

a(n) is the n-th moment of the discrete weight function W(x) = (3/4)*sum(k>=0, Dirac(x-3*k)/4^k), n>=1.

a(n) ~ n! * 3^(n+1) / ((log(2))^(n+1) * 2^(n+3)). - Vaclav Kotesovec, Jul 09 2018

G.f.: Sum_{j>=0} j!*x^j / Product_{k=1..j} (1 - 3*k*x). - Ilya Gutkovskiy, Apr 04 2019

EXAMPLE

a(5) = 729*hypergeom([2,2,2,2,2],[1,1,1,1],1/4)/16 = 3081.

MAPLE

S:= series(3/(4-exp(3*x)), x, 51):

seq(coeff(S, x, n)*n!, n=0..50); # Robert Israel, Sep 03 2015

MATHEMATICA

a[n_] := 3^(n+1)/4 HurwitzLerchPhi[1/4, -n, 0];

Table[a[n], {n, 0, 20}] (* Jean-Fran├žois Alcover, Sep 18 2018 *)

PROG

(PARI) a(n) = sum(k=0, n, stirling(n, k, 2)*k!*3^(n-k)); \\ Michel Marcus, Sep 03 2015

CROSSREFS

Cf. A000670, A094418, A004123 A032033, A094417, A122704.

Sequence in context: A218496 A144792 A291846 * A001828 A084845 A198079

Adjacent sequences:  A255924 A255925 A255926 * A255928 A255929 A255930

KEYWORD

nonn,changed

AUTHOR

Karol A. Penson, Sep 03 2015

EXTENSIONS

a(0)=1 prepended by Alois P. Heinz, Sep 18 2018

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 April 18 16:45 EDT 2019. Contains 322209 sequences. (Running on oeis4.)