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

Author

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

Keywords

• nonn

Links

• Eric Weisstein's World of Mathematics, Farey Sequence.

Crossrefs

Cf. A025527, A093593.

Programs

Mathematica

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

Formula

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