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 A245336 #17 Aug 02 2025 06:26:39 %S A245336 0,1,2,3,4,5,6,7,7,8,9,10,11,12,13,14,13,14,15,16,17,18,19,20,18,19, %T A245336 20,21,22,23,24,25,22,23,24,25,26,27,28,29,25,26,27,28,29,30,31,32,27, %U A245336 28,29,30,31,32,33,34,28,29,30,31,32,33,34,35,28,29,30,31 %N A245336 Sum of digits of n written in fractional base 8/7. %C A245336 The base 8/7 expansion is unique and thus the sum of digits function is well-defined. %H A245336 Amiram Eldar, <a href="/A245336/b245336.txt">Table of n, a(n) for n = 0..10000</a> %H A245336 <a href="/index/Ba#base_fractional">Index entries for sequences related to fractional bases</a>. %F A245336 a(n) = A007953(A024649(n)). %e A245336 In base 8/7 the number 14 is represented by 76 and so a(14) = 7 + 6 = 13. %t A245336 a[n_] := a[n] = If[n == 0, 0, a[7 * Floor[n/8]] + Mod[n, 8]]; Array[a, 100, 0] (* _Amiram Eldar_, Aug 02 2025 *) %o A245336 (Sage) # uses [basepqsum from A245355] %o A245336 [basepqsum(8,7,w) for w in [0..200]] %o A245336 (PARI) a(n) = if(n == 0, 0, a(n\8 * 7) + n % 8); \\ _Amiram Eldar_, Aug 02 2025 %Y A245336 Cf. A000120, A007953, A024649, A053829, A244040. %K A245336 nonn,base,easy %O A245336 0,3 %A A245336 _Hailey R. Olafson_, Jul 18 2014