A359045 a(n) = Sum_{1<=i<j<k<=n} b(i)*b(j)*b(k), where b(m) = A020985(m).

0, 0, 0, -1, -2, -2, -4, -5, -4, 0, 8, -5, -12, -14, -16, -17, -20, -20, -16, -25, -22, -14, -28, -21, -34, -40, -40, -45, -46, -42, -52, -49, -40, -24, 0, -33, -10, 22, -20, 11, 52, 104, 168, 91, 28, -22, 16, -33, -70, -96, -112, -105, -120, -126, -128, -133

Offset

0,5

Links

Table of n, a(n) for n=0..55.

Formula

a(n) = A213626(n)-A213786(n).

Prog

(Python)
def A359045(n): return sum((-1 if (i&(i>>1)).bit_count()&1 else 1)*sum((-1 if (j&(j>>1)).bit_count()&1 else 1)*sum(-1 if (k&(k>>1)).bit_count()&1 else 1 for k in range(j+1, n+1)) for j in range(i+1, n+1)) for i in range(1, n+1))

Crossrefs

Cf. A020985, A190173, A213626, A213786, A213787.

Sequence in context: A347717 A130265 A368156 * A187214 A179821 A292272

Adjacent sequences: A359042 A359043 A359044 * A359046 A359047 A359048

Keyword

sign

Author

Chai Wah Wu, Feb 12 2023

Status

approved