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A082681
Denominator of Sum_{i=n(n-1)/2+1..n(n+1)/2} 1/i.
2
1, 6, 60, 2520, 20020, 1627920, 124324200, 1694579040, 446626220040, 73706596563600, 35444732266944, 24569517992362200, 3290057629552053360, 551042196782556679200, 71028805196838414285360
OFFSET
1,2
PROG
(PARI) a(n) = denominator(sum(i = n*(n-1)/2+1, n*(n+1)/2, 1/i)); \\ Michel Marcus, Aug 29 2013
CROSSREFS
Numerator is in A081971. a(n) is a divisor of A061431(n).
Sequence in context: A010574 A363789 A271682 * A061431 A261523 A318131
KEYWORD
nonn,frac
AUTHOR
Dean Hickerson, Apr 10 2003
STATUS
approved