0,3

The base 7/3 expansion is unique, and thus the sum of digits function is well-defined.

Table of n, a(n) for n=0..69.

In base 7/3 the number 7 is represented by 30 and so a(7) = 3 + 0 = 3.

(Sage)

def base73sum(n):

....L=[n]

....i=1

....while L[i-1]>=7:

........x=L[i-1]

........L[i-1]=x.mod(3)

........L.append(3*floor(x/7))

........i+=1

....return sum(L)

[base73sum(y) for y in [0..200]]

Cf. A024640, A053828, A007953.

Sequence in context: A082120 A104148 A286450 * A323074 A195153 A323081

Adjacent sequences: A245341 A245342 A245343 * A245345 A245346 A245347

nonn,base

James Van Alstine, Jul 18 2014

approved