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 A269624 #12 Apr 11 2016 09:00:20 %S A269624 1,2,3,2,1,2,3,3,2,1,2,3,4,3,2,3,4,4,3,2,3,4,5,4,3,4,5,5,4,3,4,5,5,4, %T A269624 3,4,5,4,3,2,3,4,4,3,2,3,4,3,2,1,2,3,4,3,2,3,4,4,3,2,3,4,5,4,3,4,5,5, %U A269624 4,3,4,5,6,5,4,5,6,5,4,3,4,5,5,4,3,4,5,4,3,2,3,4,4,3,2,3,4,3,2,1,2,3,4,3,2 %N A269624 Length of the shortest generalized Roman numeral representation of n. %C A269624 In generalized Roman numerals, any sequence of characters from I,V,X,L,C,D,M can be interpreted uniquely as an (possibly negative) integer. So for instance IIX = 10 - 2 = 8 and IVXX = 20 - (5 - 1) = 16. The rule is: 1. First look for the first instance of the largest character in the string. 2. Everything preceding it is recursively evaluated and subtracted from the value. 3. Everything after it is recursively evaluated and added to the value. %e A269624 For numbers up to 50, one possible shortest representation is: I, II, III, IV, V, VI, VII, IIX, IX, X, XI, XII, XIII, XIV, XV, XVI, XVII, XIIX, XIX, XX, XXI, XXII, XXIII, XXIV, XXV, XXVI, XXVII, XXIIX, XXIX, XXX, XXXI, XXXII, XVIIL, XVIL, XVL, XVLI, XVLII, XIIL, XIL, XL, XLI, XLII, VIIL, VIL, VL, VLI, VLII, IIL, IL, L. %Y A269624 Cf. A006968. %K A269624 nonn,base %O A269624 1,2 %A A269624 _David Spies_, Mar 01 2016