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!)
A128061 a(n) = numerator of b(n), where sum{m>=0} b(m)*x^m/m! = x/(sum{m>=1} H(m) x^m/m!) = exp(-x)*x/(sum{m>=1} x^m (-1)^(m+1)/(m!*m)). (H(m) = sum{k=1 to m} 1/k.). 1

%I #11 Dec 29 2023 10:58:11

%S 1,-3,37,-29,2761,-97,-268271,14759,2804929,-9435089,3731508001,

%T 1185970223,-264025807957621,44820288709817,4570382525453089,

%U -336032650312339,23787999916667875201,4316502548043120587,-4994567510209019657318207

%N a(n) = numerator of b(n), where sum{m>=0} b(m)*x^m/m! = x/(sum{m>=1} H(m) x^m/m!) = exp(-x)*x/(sum{m>=1} x^m (-1)^(m+1)/(m!*m)). (H(m) = sum{k=1 to m} 1/k.).

%F b(0)=1. b(n) = -sum{k=1 to n} binomial(n,k) H(k+1) b(n-k)/(k+1).

%e 1/(1 + x * 3/(2 * 2) + x^2 * 11/(6 * 6) + x^3 * 25/(12 * 24) +...) = 1 -x * 3/4 + x^2 * 37/72 -x^3 * 29/96 ...

%t b[0] = 1;b[n_] := b[n] = -Sum[Binomial[n, k] *HarmonicNumber[k + 1]*b[n - k]/(k + 1), {k, n}];Numerator[Array[b, 20, 0]] (* _Ray Chandler_, Feb 19 2007 *)

%Y Cf. A128062.

%K frac,sign

%O 0,2

%A _Leroy Quet_, Feb 13 2007

%E Extended by _Ray Chandler_, Feb 19 2007

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 29 04:13 EDT 2024. Contains 374727 sequences. (Running on oeis4.)