A261869 First differences of A055615.

-3, -1, 3, -5, 11, -13, 7, 0, 10, -21, 11, -13, 27, 1, -15, -17, 17, -19, 19, 21, 1, -45, 23, 0, 26, -26, 0, -29, -1, -1, 31, 33, 1, 1, -35, -37, 75, 1, -39, -41, -1, -1, 43, 0, 46, -93, 47, 0, 0, 51, -51, -53, 53, 55, -55, 57, 1, -117, 59, -61, 123, -62, 0

Offset: 1

Author

Reinhard Zumkeller, Sep 04 2015

Keywords

• sign

Comments

a(n) = (n+1)*mu(n+1) - n*mu(n), where mu = A008683 (Moebius function);

a(A068781(n)) = 0;

abs(a(n)) <= 2*n + 1.

Links

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

Crossrefs

Cf. A008683, A055615, A068781, A261890 (first differences).

Programs

Haskell

import Data.List (genericIndex)
a261869 n = genericIndex a261869_list (n - 1)
a261869_list = zipWith (-) (tail a055615_list) a055615_list

Mathematica

#[[2]]-#[[1]]&/@Partition[Table[n*MoebiusMu[n],{n,70}],2,1] (* Harvey P. Dale, Apr 17 2016 *)