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%I #12 Mar 16 2020 16:31:49
%S 0,1,2,3,4,5,6,2,3,4,5,6,7,8,4,5,6,7,8,9,10,6,7,8,9,10,11,12,3,4,5,6,
%T 7,8,9,5,6,7,8,9,10,11,7,8,9,10,11,12,13,4,5,6,7,8,9,10,6,7,8,9,10,11,
%U 12,8,9,10,11,12,13,14,10,11,12,13,14,15,16,7
%N Sum of digits of n written in fractional base 7/2.
%C The base 7/2 expansion is unique and thus the sum of digits function is well-defined.
%F a(n) = A007953(A024639(n)).
%e In base 7/2 the number 14 is represented by 40 and so a(14) = 4 + 0 = 4.
%o (Sage) # uses [basepqsum from A245355]
%o [basepqsum(7,2,w) for w in [0..200]]
%Y Cf. A007953, A000120, A024639, A053828, A244040.
%K nonn,base
%O 0,3
%A _Hailey R. Olafson_, Jul 18 2014