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A120076 Numerators of row sums of rational triangle A120072/A120073. 3
3, 37, 169, 4549, 4769, 241481, 989549, 9072541, 1841321, 225467009, 227698469, 38801207261, 39076419341, 196577627041, 790503882349, 229526961468061, 230480866420061, 83512167402400421, 3351610394325821 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

COMMENTS

The corresponding denominators are given by A120077.

See the W. Lang link under A120072 for more details.

LINKS

Table of n, a(n) for n=2..20.

FORMULA

a(n)=numerator(r(m)), with the rationals r(m):=sum(A120072(m,n)/A120073(m,n),n=1..m-1),m>=2.

The rationals are r(m)= Zeta(2;m-1) - (m-1)/m^2, m>=2, with the partial sums Zeta(2;n):=sum(1/k^2,k=1..n). See the W. Lang link under A103345.

O.g.f. for the rationals r(m), m>=2: log(1-x) + polylog(2,x)/(1-x).

EXAMPLE

The rationals A120076(m)/A120077(m), m>=2, begin with [3/4, 37/36,

169/144, 4549/3600, 4769/3600,..].

CROSSREFS

Sequence in context: A109835 A066364 A106995 * A119938 A232303 A196978

Adjacent sequences:  A120073 A120074 A120075 * A120077 A120078 A120079

KEYWORD

nonn,easy,frac

AUTHOR

Wolfdieter Lang, Jul 20 2006

STATUS

approved

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Last modified November 29 14:08 EST 2021. Contains 349416 sequences. (Running on oeis4.)