0,3

The base 7/2 expansion is unique and thus the sum of digits function is well-defined.

Table of n, a(n) for n=0..77.

a(n) = A007953(A024639(n)).

In base 7/2 the number 14 is represented by 40 and so a(14) = 4 + 0 = 4.

(Sage)

def base72sum(n):

....L=[n]

....i=1

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

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

........L[i-1]=x.mod(7)

........L.append(2*floor(x/7))

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

....return sum(L)

[base72sum(w) for w in [0..200]]

A007953, A000120, A024639, A053828, A244040

Sequence in context: A105257 A125937 A173526 * A203580 A043266 A082120

Adjacent sequences: A245339 A245340 A245341 * A245343 A245344 A245345

nonn,base

Hailey R. Olafson, Jul 18 2014

approved