%I #9 Mar 31 2021 10:11:04
%S 1,0,-4,-8,-32,-32,-128,-256,-512,-512,-2048,-4096,-12288,-16384,
%T -16384,-32768,-131072,-262144,-786432,-1572864,-2097152,-2097152,
%U -8388608,-16777216,-33554432,-33554432,-67108864,-134217728,-536870912,-1610612736,-4294967296
%N A002321*A000079.
%C Appears to be the determinant of n X n (-1,1) matrix defined by A(i,j)=1 if j=1 or i divides j else -1.
%C Appears also to be the determinant of n X n (-i/j,i/j) matrix defined by A(i,j)=i/j if j=1 or i divides j else -i/j.
%F a(n) = 2^(n-1)*A002321(n). - _Chai Wah Wu_, Mar 30 2021
%o (Python)
%o from functools import lru_cache
%o @lru_cache(maxsize=None)
%o def A162459(n):
%o if n == 0:
%o return 0
%o c, j = n, 2
%o k1 = n//j
%o while k1 > 1:
%o j2 = n//k1 + 1
%o c += (j2-j)*A162459(k1)//2**(k1-1)
%o j, k1 = j2, n//j2
%o return 2**(n-1)*(j-c) # _Chai Wah Wu_, Mar 30 2021
%Y Cf. A002321, A000079.
%K sign
%O 1,3
%A _Mats Granvik_, Jul 04 2009