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A004092 Sum of digits of even numbers. 3
0, 2, 4, 6, 8, 1, 3, 5, 7, 9, 2, 4, 6, 8, 10, 3, 5, 7, 9, 11, 4, 6, 8, 10, 12, 5, 7, 9, 11, 13, 6, 8, 10, 12, 14, 7, 9, 11, 13, 15, 8, 10, 12, 14, 16, 9, 11, 13, 15, 17, 1, 3, 5 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..10000

FORMULA

a(n) = 2n - 9*Sum_{k=1..1+floor(log_10(2n))} floor( n/(5*10^(k-1)) ). - Anthony Browne, Jun 18 2016

a(n) = A007953(2n). - Alois P. Heinz, Apr 11 2018

MATHEMATICA

Table[Sum[DigitCount[2*n][[i]]*i, {i, 9}], {n, 0, 100}] (* G. C. Greubel, Jun 19 2016 *)

PROG

(PARI) a(n)=sumdigits(2*n) \\ Charles R Greathouse IV, Jun 19 2016

CROSSREFS

Cf. A007953.

Sequence in context: A146082 A169909 A180592 * A133311 A088402 A077492

Adjacent sequences:  A004089 A004090 A004091 * A004093 A004094 A004095

KEYWORD

nonn,base,easy

AUTHOR

N. J. A. Sloane, Dec 11 1996

STATUS

approved

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Last modified February 20 00:28 EST 2019. Contains 320329 sequences. (Running on oeis4.)