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A245335
Sum of digits of n in fractional base 5/4.
1
0, 1, 2, 3, 4, 4, 5, 6, 7, 8, 7, 8, 9, 10, 11, 9, 10, 11, 12, 13, 10, 11, 12, 13, 14, 10, 11, 12, 13, 14, 14, 15, 16, 17, 18, 13, 14, 15, 16, 17, 16, 17, 18, 19, 20, 14, 15, 16, 17, 18, 16, 17, 18, 19, 20, 20, 21, 22, 23, 24, 17, 18, 19, 20, 21, 18, 19, 20, 21
OFFSET
0,3
COMMENTS
The base 5/4 expansion is unique and thus the sum of digits function is well-defined.
FORMULA
a(n) = A007953(A024634(n)). - Kevin Ryde, Aug 11 2023
EXAMPLE
In base 5/4 the number 7 is represented by 42 and so a(7)=4+2=6.
PROG
(Sage) # uses [basepqsum from A245355]
[basepqsum(5, 4, y) for y in [0..200]]
(PARI) a(n) = my(ret=0, r); while(n, [n, r]=divrem(n, 5); ret+=r; n<<=2); ret; \\ Kevin Ryde, Aug 11 2023
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
James Van Alstine, Jul 18 2014
STATUS
approved