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A173639 Numbers n such that the sum of the digits of 11*n is odd. 1
19, 28, 29, 37, 38, 39, 46, 47, 48, 49, 55, 56, 57, 58, 59, 64, 65, 66, 67, 68, 69, 73, 74, 75, 76, 77, 78, 79, 82, 83, 84, 85, 86, 87, 88, 89, 119, 128, 129, 137, 138, 139, 146, 147, 148, 149 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Note that the first 18 multiples of 11 have even digital sums.

Indices of odd entries in A136614. - R. J. Mathar, Nov 23 2010

a(n) = A075517(n+9) = A248013(n+10) for n <= 36. - Giovanni Resta, Sep 04 2017

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

EXAMPLE

19 is on the list because 11*19 = 209 and 2+0+9 is odd.

MAPLE

L := []; for n to 150 do if `mod`(add(i, i = convert(11*n, base, 10)), 2) = 1 then L := [op(L), n] end if end do; L;

MATHEMATICA

Select[Range[200], OddQ[Total[IntegerDigits[11#]]]&] (* Harvey P. Dale, May 28 2012 *)

PROG

(Python)

ans = []

for n in range(1, 151):

..N, s = 11*n, 0

..while N:

....s += N % 10

....N = N / 10

..if s % 2 == 1:

....ans.append(n)

print ans

(Haskell)

a173639 n = a173639_list !! (n-1)

a173639_list = filter (odd . a007953 . (* 11)) [0..]

-- Reinhard Zumkeller, Jul 05 2014

CROSSREFS

Cf. A008593, A007953.

Sequence in context: A304367 A298638 A291884 * A091448 A067777 A065207

Adjacent sequences:  A173636 A173637 A173638 * A173640 A173641 A173642

KEYWORD

nonn,base

AUTHOR

David Radcliffe, Nov 23 2010

STATUS

approved

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Last modified October 19 04:40 EDT 2019. Contains 328211 sequences. (Running on oeis4.)