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 A284580 #8 Apr 15 2017 09:17:45 %S A284580 1,1,1,2,1,1,2,3,1,1,1,2,2,2,3,4,1,1,1,2,1,1,2,3,2,2,2,4,3,3,4,5,1,1, %T A284580 1,2,1,1,2,3,1,1,1,2,2,2,3,4,2,2,2,4,2,2,4,6,3,3,3,6,4,4,5,6,1,1,1,2, %U A284580 1,1,2,3,1,1,1,2,2,2,3,4,1,1,1,2,1,1,2,3,2,2,2,4,3,3,4,5,2,2,2,4,2,2,4,6,2,2,2,4,4,4,6,8,3,3,3,6,3,3,6,5,4 %N A284580 Carryless base-2 product (A048720) of lengths of runs of 1-bits in binary representation of n. %H A284580 Antti Karttunen, <a href="/A284580/b284580.txt">Table of n, a(n) for n = 0..10922</a> %H A284580 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a> %e A284580 a(119) = 5, as 119 is "1110111" in binary, and A048720(3,3) = 5. %o A284580 (Scheme) (define (A284580 n) (reduce A048720bi 1 (bisect (reverse (binexp->runcount1list n)) (- 1 (modulo n 2))))) ;; Where A048720bi is a two-argument function implementing carryless binary product, A048720. For bisect and binexp->runcount1list, see under A227349. %Y A284580 Cf. A003714 (positions of ones). %Y A284580 Cf. A048720, A284579. %Y A284580 Differs from similar A227349 for the first time at n=119, where a(119) = 5, while A227349(119) = 9. %K A284580 nonn,base %O A284580 0,4 %A A284580 _Antti Karttunen_, Apr 14 2017