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 A245343 #24 Jul 31 2025 02:40:50 %S A245343 0,1,2,3,4,3,4,5,6,7,4,5,6,7,8,7,8,9,10,11,6,7,8,9,10,7,8,9,10,11,10, %T A245343 11,12,13,14,7,8,9,10,11,10,11,12,13,14,9,10,11,12,13,10,11,12,13,14, %U A245343 13,14,15,16,17,8,9,10,11,12,11,12,13,14,15 %N A245343 Sum of digits of n written in fractional base 5/3. %C A245343 The base 5/3 expansion is unique and thus the sum of digits function is well-defined. %H A245343 Amiram Eldar, <a href="/A245343/b245343.txt">Table of n, a(n) for n = 0..10000</a> %H A245343 <a href="/index/Ba#base_fractional">Index entries for sequences related to fractional bases</a>. %F A245343 a(n) = A007953(A024633(n)). - _Amiram Eldar_, Jul 30 2025 %e A245343 In base 5/3 the number 7 is represented by 32 and so a(7) = 3+2 = 5. %t A245343 a[n_] := a[n] = If[n == 0, 0, a[3 * Floor[n/5]] + Mod[n, 5]]; Array[a, 100, 0] (* _Amiram Eldar_, Jul 30 2025 *) %o A245343 (Sage) # uses [basepqsum from A245355] %o A245343 [basepqsum(5,3,y) for y in [0..200]] %o A245343 (PARI) a(n) = if(n == 0, 0, a(n\5 * 3) + n % 5); \\ _Amiram Eldar_, Jul 30 2025 %Y A245343 Cf. A024633, A007953, A053824. %K A245343 nonn,base,easy %O A245343 0,3 %A A245343 _James Van Alstine_, Jul 18 2014 %E A245343 Name corrected by _Bernard Schott_, Mar 18 2020