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 A260022 #13 Jun 20 2022 13:16:30 %S A260022 1,3,7,13,29,55,115,209,465,883,1847,3357,7437,14087,29443,53505, %T A260022 119041,226051,472839,859405,1903901,3606327,7537523,13697489, %U A260022 30474449,57868403,121045047,220004381,487391245,923205639,1929576451,3506503681,7801470977,14814478339,30987976711,56321966093 %N A260022 A bisection of A006921. %H A260022 Reinhard Zumkeller, <a href="/A260022/b260022.txt">Table of n, a(n) for n = 0..1000</a> %F A260022 a(n) = A006921(2*n). %o A260022 (Haskell) %o A260022 a260022 = a006921 . (* 2) -- _Reinhard Zumkeller_, Jul 14 2015 %o A260022 (Python) %o A260022 def A260022(n): return sum(int(not r & ~(2*n-r))*2**(n-r) for r in range(n+1)) # _Chai Wah Wu_, Jun 20 2022 %Y A260022 Cf. A006921, A168081. %K A260022 nonn %O A260022 0,2 %A A260022 _N. J. A. Sloane_, Jul 14 2015