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!)
A145613 Numerator of the polynomial A_l(x) = sum_{d=1..l-1} x^(l-d)/d for index l=2n+1 evaluated at x=3. 2
21, 393, 17731, 2234571, 20111503, 1991042087, 33278851497, 119803867191, 54989975121893, 15672142912044093, 987345003473390379, 204380415719298965303, 9197118707369867504211, 248322205098990353297597 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

For denominators see A145614. For general properties of A_l(x) see A145609.

LINKS

Table of n, a(n) for n=1..14.

MAPLE

A := proc(l, x) add(x^(l-d)/d, d=1..l-1) ; end: A145613 := proc(n) numer( A(2*n+1, 3)) ; end: seq(A145613(n), n=1..20) ; # R. J. Mathar, Aug 21 2009

MATHEMATICA

m = 3; aa = {}; Do[k = 0; Do[k = k + m^(2 r + 1 - d)/d, {d, 1, 2 r}]; AppendTo[aa, Numerator[k]], {r, 1, 25}]; aa (* Artur Jasinski *)

a[n_, m_]:=Integrate[(m-x^n)/(m-x), {x, 0, 1}]+(m^n-m)Log[m/(m-1)]

Table[3 a[2 n, 3] //FullSimplify //Numerator, {n, 1, 10}]  (* Gerry Martens , Jun 04 2016 *)

CROSSREFS

Cf. A145609 - A145640.

Sequence in context: A256178 A094172 A296723 * A212786 A015677 A285396

Adjacent sequences:  A145610 A145611 A145612 * A145614 A145615 A145616

KEYWORD

frac,nonn

AUTHOR

Artur Jasinski, Oct 14 2008

EXTENSIONS

Edited by R. J. Mathar, Aug 21 2009

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 September 19 10:53 EDT 2021. Contains 347556 sequences. (Running on oeis4.)