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 A090792 #8 Mar 30 2012 18:39:22 %S A090792 1,3,5,5,9,9,9,9,17,17,17,17,17,17,17,17,31,31,31,31,31,31,31,31,31, %T A090792 31,31,31,31,31,31,31,57,57,57,57,57,57,57,57,57,57,57,57,57,57,57,57, %U A090792 57,57,57,57,57,57,57,57,57,57,57,57,57,57,57,57,105,105,105,105,105,105 %N A090792 a(0)=1; for n>0, a(n)=a([n/2])+a([n/4])+a([n/8]). %F A090792 n>0 a(n) = A000213([log(n)/log(2)]+3) %o A090792 (PARI) a(n)=if(n<1,1,a(floor(n/2))+a(floor(n/4))+a(floor(n/8))) %Y A090792 Cf. A083662. %K A090792 nonn %O A090792 0,2 %A A090792 _Benoit Cloitre_, Oct 24 2004