A055064 - OEIS

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

(list; graph; refs; listen; history; text; internal format)

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