A239122 Partial sums of A061019.

1, -1, -4, 0, -5, 1, -6, -14, -5, 5, -6, -18, -31, -17, -2, 14, -3, -21, -40, -60, -39, -17, -40, -16, 9, 35, 8, -20, -49, -79, -110, -142, -109, -75, -40, -4, -41, -3, 36, 76, 35, -7, -50, -94, -139, -93, -140, -188, -139, -189, -138, -190, -243, -189, -134

Offset: 1

Author

Reinhard Zumkeller, Mar 10 2014

Keywords

• sign

Links

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

Crossrefs

Cf. A002819.

Programs

Haskell

a239122 n = a239122_list !! (n-1)
a239122_list = scanl1 (+) a061019_list

Mathematica

Accumulate[Table[n*(-1)^PrimeOmega[n],{n,70}]] (* Harvey P. Dale, Apr 02 2015 *)

Python

from functools import reduce
from operator import ixor
from sympy import factorint
def A239122(n): return sum(-i if reduce(ixor, factorint(i).values(), 0)&1 else i for i in range(1,n+1)) # Chai Wah Wu, Jan 03 2023