A068341 Sum{k=1 to n} mu(k) mu(n+1-k), where mu(k) is the Moebius function.

1, -2, -1, 2, -1, 4, -2, 0, 3, 0, -1, -2, 1, 2, 6, -8, 0, -2, 3, 0, 5, -4, 2, -2, 1, -2, 1, -6, 5, -2, 4, -4, 5, 0, 10, -6, -7, -2, 2, -4, 3, -2, 1, -4, -1, 4, 10, 4, 4, -14, -1, -4, 8, 2, 2, -12, -3, 2, 13, 10, -11, -10, -2, -6, 13, -6, -5, -8, 5, 2, 18, 10, -5, -6, -9, 0

Offset: 1

Author

Leroy Quet, Feb 27 2002

Keywords

• sign

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Programs

Haskell

a068341 n = a068341_list !! (n-1)
a068341_list = f 1 [] where
   f x ms = (sum $ zipWith (*) ms' $ reverse ms') : f (x + 1) ms' where
     ms' = (a008683 x) : ms
-- Reinhard Zumkeller, Aug 03 2012

Mathematica

a[n_] := Sum[ MoebiusMu[k]*MoebiusMu[n + 1 - k], {k, 1, n}]; Table[ a[n], {n, 1, 76}] (* Jean-François Alcover, Oct 10 2011 *)