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A145660 a(n) = numerator of amazing polynomial of genus 1 and level n for m = 4 = A[1,n](4) 1
0, 4, 18, 220, 883, 17672, 23566, 659868, 5278979, 95021762, 380087174, 16723836916, 66895348819, 3478558152448, 13914232622662, 11131386100532, 178102177617521, 3027737019533893, 4036982692723202, 306810684647167556 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

COMMENTS

For numerator of amazing polynomial of genus 1 and level n for m = 1 see A001008.

Definition: Amazing polynomial A[1,2n+1](m) = A[genus 1,level n] is here defined as

Sum[m^(n - d)/d,{d,1,n-1}]

Few first A[1,n](m):

n=1: A[1,1](m)= 0

n=2: A[1,2](m)= m

n=3: A[1,3](m)= m/2 + m^2

n=4: A[1,4](m)= m/4 + m^2/3 + m^3/2 + m^4

General formula which uses amazing polynomials is following (*Artur Jasinski*):

(1/(n+1))Hypergeometric2F1[1,n,n+1,1/m] =

Sum[m^(-x)(1/(x+n),{x,0,Infinity}] =

m^(n)ArcTanh[(2m-1)/(2m^2-2m+1)]-A[1,n](m) =

m^(n)Log[m/(m-1)]-A[1,n](m)

MAPLE

A145660 := proc(n) add( 4^(n-d)/d, d=1..n-1) ; numer(%) ; end proc: # R. J. Mathar, Feb 01 2011

MATHEMATICA

m = 4; aa = {}; Do[k = 0; Do[k = k + m^(r - d)/d, {d, 1, r - 1}]; AppendTo[aa, Numerator[k]], {r, 1, 30}]; aa (*Artur Jasinski*)

CROSSREFS

A145609-A145640, A145656-A145687.

Sequence in context: A197786 A071173 A143993 * A156522 A086400 A082022

Adjacent sequences:  A145657 A145658 A145659 * A145661 A145662 A145663

KEYWORD

frac,nonn

AUTHOR

Artur Jasinski (grafix(AT)csl.pl), Oct 16 2008

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Last modified February 17 16:39 EST 2012. Contains 206058 sequences.