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 A035515 #19 Jul 02 2025 16:01:56 %S A035515 0,1,2,3,13,5,15,25,8,18,28,38,138,13,113,213,313,1313,513,1513,2513, %T A035515 21,121,221,321,1321,521,1521,2521,821,1821,2821,3821,13821,34,134, %U A035515 234,334,1334,534,1534,2534,834,1834,2834,3834,13834,1334,11334,21334 %N A035515 Zeckendorf expansion of n: repeatedly subtract the largest Fibonacci number you can until nothing remains. Little-endian concatenation of decimals. %D A035515 Zeckendorf, E., Représentation des nombres naturels par une somme des nombres de Fibonacci ou de nombres de Lucas, Bull. Soc. Roy. Sci. Liège 41, 179-182, 1972. %H A035515 Reinhard Zumkeller, <a href="/A035515/b035515.txt">Table of n, a(n) for n = 0..10000</a> %H A035515 N. J. A. Sloane, <a href="/classic.html#WYTH">Classic Sequences</a> %e A035515 16 = 13 + 3, so a(16)=3_13 => 313. %o A035515 (Haskell) %o A035515 a035515 n = a035515_list !! (n-1) %o A035515 a035515_list = map (read . concatMap show) a035517_tabf :: [Integer] %o A035515 -- _Reinhard Zumkeller_, Mar 10 2013 %Y A035515 Cf. A035517, A035514, A035516. %K A035515 nonn,easy,base %O A035515 0,3 %A A035515 _N. J. A. Sloane_ %E A035515 More terms from _James Sellers_, Dec 13 1999