A093627 a(n) = lcm(1,2,3,...,n) * (sum of Farey fractions of order n).

1, 3, 15, 42, 330, 390, 3990, 9660, 36540, 41580, 595980, 651420, 10630620, 11711700, 13153140, 29189160, 594233640, 630990360, 14083949880, 15015120120, 16411875480, 17575838280, 463140798120, 484557713640, 2690500012200

Offset

1,2

Links

Table of n, a(n) for n=1..25.

Eric Weisstein's World of Mathematics, Farey Sequence.

Formula

a(n) = A093593(n)/A025527(n).

Mathematica

Farey[n_] := Union[ Flatten[ Join[{0}, Table[a/b, {b, n}, {a, b}]]]]; Table[LCM @@ Range[n] Plus @@ Farey[n], {n, 26}]

Crossrefs

Cf. A025527, A093593.

Sequence in context: A219085 A346142 A366576 * A192060 A316642 A146805

Adjacent sequences: A093624 A093625 A093626 * A093628 A093629 A093630

Keyword

nonn

Author

Robert G. Wilson v and Clark Kimberling, Apr 06 2004

Status

approved