A210524 a(n) = n - sum of even digits of n.

0, 1, 0, 3, 0, 5, 0, 7, 0, 9, 10, 11, 10, 13, 10, 15, 10, 17, 10, 19, 18, 19, 18, 21, 18, 23, 18, 25, 18, 27, 30, 31, 30, 33, 30, 35, 30, 37, 30, 39, 36, 37, 36, 39, 36, 41, 36, 43, 36, 45, 50, 51, 50, 53, 50, 55, 50, 57, 50, 59, 54, 55, 54, 57, 54, 59, 54, 61

Offset: 0

Author

Marco Piazzalunga, Jan 27 2013

Keywords

• nonn
• base
• easy

Comments

In even positions there are odd terms.

The difference between n and even digits of n and n has odd and even digits gives even terms finishing with 0.

Examples

			a(14) = 14 - 4 = 10.
a(28) = 28 - 2 - 8 = 18.
		

Crossrefs

Cf. A066568.

Programs

Mathematica

Table[n-Total[Select[IntegerDigits[n],EvenQ]],{n,0,90}] (* Harvey P. Dale, May 20 2017 *)

PARI

a(n) = {digs = digits(n, 10); return (n - sum(i=1, #digs, digs[i]*(1 - (digs[i] % 2))));} \\ Michel Marcus, Jul 15 2013

Formula

a(n) ~ n. a(n) = n mod 2. - Charles R Greathouse IV, Jan 28 2013