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A111876 Denominator of sum{k=0..n, 1/((k+1)(2k+1))}. 2
1, 6, 30, 420, 1260, 13860, 180180, 72072, 1225224, 116396280, 116396280, 2677114440, 13385572200, 5736673800, 166363540200, 10314539492400, 10314539492400, 72201776446800, 2671465728531600, 2671465728531600 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Denominator of digamma(n+3/2)-digamma(n+2)+2log(2). Numerator is A082687.

sum{k=0..n, 1/((k+1)(2k+1))}=2*(n+1)*int(x^n*log(1+sqrt(x)),x=0..1)

LINKS

Table of n, a(n) for n=0..19.

FORMULA

a(n) = lcm(1..2n+2)/2. - Paul Barry, Jul 03 2006

CROSSREFS

Sequence in context: A232978 A332041 A201135 * A119634 A256545 A075591

Adjacent sequences:  A111873 A111874 A111875 * A111877 A111878 A111879

KEYWORD

easy,nonn,frac

AUTHOR

Paul Barry, Aug 19 2005

STATUS

approved

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Last modified September 23 16:29 EDT 2021. Contains 347618 sequences. (Running on oeis4.)