The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
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!)
A144756 Partial products of successive terms of A017101; a(0)=1 . 4

%I #29 Dec 20 2022 03:49:46

%S 1,3,33,627,16929,592515,25478145,1299385395,76663738305,

%T 5136470466435,385235284982625,31974528653557875,2909682107473766625,

%U 288058528639902895875,30822262564469609858625,3544560194914005133741875,435980903974422631450250625,57113498420649364719982831875

%N Partial products of successive terms of A017101; a(0)=1 .

%F a(n) = Sum_{k=0..n} A132393(n,k)*3^k*8^(n-k).

%F a(n) = (-5)^n*sum_{k=0..n} (8/5)^k*s(n+1,n+1-k), where s(n,k) are the Stirling numbers of the first kind, A048994. - _Mircea Merca_, May 03 2012

%F G.f.: 2/G(0), where G(k)= 1 + 1/(1 - 2*x*(8*k+3)/(2*x*(8*k+3) - 1 + 16*x*(k+1)/G(k+1))); (continued fraction). - _Sergei N. Gladkovskii_, May 30 2013

%F a(n) +(-8*n+5)*a(n-1)=0. - _R. J. Mathar_, Sep 04 2016

%F From _Ilya Gutkovskiy_, Mar 23 2017: (Start)

%F E.g.f.: 1/(1 - 8*x)^(3/8).

%F a(n) ~ sqrt(2*Pi)*8^n*n^n/(exp(n)*n^(1/8)*Gamma(3/8)). (End)

%F Sum_{n>=0} 1/a(n) = 1 + (e/8^5)^(1/8)*(Gamma(3/8) - Gamma(3/8, 1/8)). - _Amiram Eldar_, Dec 20 2022

%e a(0)=1, a(1)=3, a(2)=3*11=33, a(3)=3*11*19=627, a(4)=3*11*19*27=16929, ...

%t Join[{1},FoldList[Times,8Range[0,20]+3]] (* _Harvey P. Dale_, Aug 11 2019 *)

%Y Cf. A001710, A001147, A008545, A011781, A017101, A032031, A047056, A048994, A144739.

%K nonn,easy

%O 0,2

%A _Philippe Deléham_, Sep 20 2008

%E a(11) corrected by _Ilya Gutkovskiy_, Mar 23 2017

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 May 14 12:12 EDT 2024. Contains 372532 sequences. (Running on oeis4.)