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A029807
a(n) = (1/(8*n)) * Sum_{d|n} mu(n/d) * binomial(2*d,d)^3.
0
1, 13, 333, 10712, 400075, 16435017, 721861385, 33308540000, 1596292110000, 78832566399375, 3989172320345245, 205979496842877048, 10817872108002076923, 576440295110730997877, 31102930647624990624975
OFFSET
1,2
PROG
(PARI) a(n) = sumdiv(n, d, moebius(n/d)*binomial(2*d, d)^3)/(8*n) \\ Michel Marcus, Jun 15 2013
CROSSREFS
Sequence in context: A142543 A258297 A266902 * A372182 A097308 A204195
KEYWORD
nonn
AUTHOR
Lionel Levine (levine(AT)ultranet.com)
EXTENSIONS
More terms from Erich Friedman
STATUS
approved