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!)
A185948 Exponential Riordan array (e^(mx),x*A000108(x)), m=3. 1

%I

%S 1,3,1,9,8,1,27,57,15,1,81,480,186,24,1,243,5505,2550,450,35,1,729,

%T 87048,42795,8760,915,48,1,2187,1780569,887733,194355,23625,1659,63,1,

%U 6561,44326656,22154580,5010768,660870,54432,2772,80,1,19683,1291851585,645896268,148808772,20586258,1862406,112140,4356,99,1,59049,43011249480,21505526325,5015422800,715608810,68717376,4590810,212400,6525,120,1

%N Exponential Riordan array (e^(mx),x*A000108(x)), m=3.

%H G. C. Greubel, <a href="/A185948/b185948.txt">Table of n, a(n) for the first 50 rows, flattened</a>

%H Vladimir Kruchinin, D. V. Kruchinin, <a href="http://arxiv.org/abs/1103.2582">Composita and their properties</a>, arXiv:1103.2582 [math.CO], 2013.

%F R(n,k,m) = (n!/(k-1)!) * Sum_{i=0..(n-k)} (m^i/i!)*binomial(2*(n-i)-k-1,n-i-1)/(n-i), k>0, m=3, R(n,0,1)=3^n.

%e [1]

%e [3,1]

%e [9,8,1]

%e [27,57,15,1]

%e [81,480,186,24,1]

%e [243,5505,2550,450,35,1]

%e [729,87048,42795,8760,915,48,1]

%e [2187,1780569,887733,194355,23625,1659,63,1]

%t R[n_, k_, m_] := (n!/(k - 1)!)*Sum[m^i/i!*Binomial[2*(n - i) - k - 1, n - i - 1]/(n - i), {i, 0, n - k}]; R[n_, 0, m_] = 3^n; Table[R[n, k, 3], {n,0,10}, {k,0,n}] // Flatten (* _G. C. Greubel_, Jul 23 2017 *)

%K nonn,tabl

%O 0,2

%A _Vladimir Kruchinin_, Feb 07 2011

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 July 5 03:37 EDT 2020. Contains 335459 sequences. (Running on oeis4.)