A071649 Sum of odd decimal digits of n.

1, 0, 3, 0, 5, 0, 7, 0, 9, 1, 2, 1, 4, 1, 6, 1, 8, 1, 10, 0, 1, 0, 3, 0, 5, 0, 7, 0, 9, 3, 4, 3, 6, 3, 8, 3, 10, 3, 12, 0, 1, 0, 3, 0, 5, 0, 7, 0, 9, 5, 6, 5, 8, 5, 10, 5, 12, 5, 14, 0, 1, 0, 3, 0, 5, 0, 7, 0, 9, 7, 8, 7, 10, 7, 12, 7, 14, 7, 16, 0, 1, 0, 3, 0, 5, 0, 7, 0, 9, 9, 10, 9

Offset: 1

Author

Reinhard Zumkeller, May 28 2002

Keywords

• nonn
• base
• easy

Crossrefs

a(n) = A007953(n) - A071648(n).

Cf. A014263, A071650.

Programs

Maple

A071649 := proc(n)
      local a,d;
      a := 0 ;
      for d in convert(n,base,10) do
        if type(d,'odd') then
            a := a+d ;
        end if;
    end do:
    a ;
end proc: # R. J. Mathar, Feb 02 2015

Mathematica

Table[Total[Select[IntegerDigits[n], OddQ[#] &]],{n,92}] (* Jayanta Basu, May 23 2013 *)

PARI

a(n)=my(d=digits(n)); sum(i=1,#d,if(d[i]%2,d[i])) \\ Charles R Greathouse IV, Apr 04 2014

PARI

A071649(n)=vecsum(select(d->bittest(d,0), digits(n))) \\ Nearly twice as fast. - M. F. Hasler, Dec 09 2018

Python

A071649 = lambda x: sum(d for d in map(int, str(x)) if d&1) # M. F. Hasler, Dec 07 2022

Formula

a(n) = 0 iff n is in A014263. - Bernard Schott, Mar 17 2023