This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A055064 #21 Oct 24 2023 03:25:20 %S A055064 0,1,8,36,167,693,2849,11459,46244,185622,743759,2974937,11907026, %T A055064 47643438,190606963,762449101,3049917900,12199777048,48799551822, %U A055064 195198666492,780796575104,3123189865122,12492766610068,49971069327602,199884317492186,799537344955292 %N A055064 a(n) = A004125(2^n) = A004125(2^n-1). %H A055064 Chai Wah Wu, <a href="/A055064/b055064.txt">Table of n, a(n) for n = 1..77</a> %F A055064 a(n) >= A006516(n-1). - _R. J. Mathar_, Apr 04 2012 %o A055064 (Python) %o A055064 from math import isqrt %o A055064 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 %Y A055064 Cf. A004125, A006516, A120444. %K A055064 nonn %O A055064 1,3 %A A055064 _David W. Wilson_, Jun 12 2000