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A130492 a(n) = denominator of Sum_{k=1..n} k^mu(n+1-k), where mu(m) = A008683(m). 3
1, 1, 2, 6, 12, 20, 10, 84, 840, 72, 630, 1320, 2772, 1560, 90090, 42, 240240, 1904, 46410, 95760, 639540, 5040, 9699690, 637560, 14316120, 92400, 176125950, 308880, 20078358300, 475020, 33845175, 7447440, 116925953760, 110880, 501401225325 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Numerator of Sum_{k=1..n} k^mu(n+1-k) is A130491(n).

LINKS

Table of n, a(n) for n=1..35.

MAPLE

A130492 := proc(n) denom(add(k^numtheory[mobius](n+1-k), k=1..n)) ; end: seq(A130492(n), n=1..40) ; # R. J. Mathar, Oct 16 2007

CROSSREFS

Cf. A130491, A080306, A080326.

Sequence in context: A340663 A139084 A086958 * A305702 A152222 A139082

Adjacent sequences:  A130489 A130490 A130491 * A130493 A130494 A130495

KEYWORD

frac,nonn

AUTHOR

Leroy Quet, May 29 2007

EXTENSIONS

More terms from R. J. Mathar, Oct 16 2007

STATUS

approved

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Last modified June 19 00:04 EDT 2021. Contains 345125 sequences. (Running on oeis4.)