A055064 a(n) = A004125(2^n) = A004125(2^n-1).

0, 1, 8, 36, 167, 693, 2849, 11459, 46244, 185622, 743759, 2974937, 11907026, 47643438, 190606963, 762449101, 3049917900, 12199777048, 48799551822, 195198666492, 780796575104, 3123189865122, 12492766610068, 49971069327602, 199884317492186, 799537344955292

Offset

1,3

Links

Chai Wah Wu, Table of n, a(n) for n = 1..77

Formula

a(n) >= A006516(n-1). - R. J. Mathar, Apr 04 2012

Prog

(Python)
from math import isqrt
def A055064(n): return ((m:=1<<n)<<n)+((s:=isqrt(m))**2*(s+1)-sum((q:=m//k)*((k<<1)+q+1) for k in range(1, s+1))>>1) # Chai Wah Wu, Oct 22 2023

Crossrefs

Cf. A004125, A006516, A120444.

Sequence in context: A200468 A200250 A207099 * A014347 A200053 A164545

Adjacent sequences: A055061 A055062 A055063 * A055065 A055066 A055067

Keyword

nonn

Author

David W. Wilson, Jun 12 2000

Status

approved