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A054684 Sum of digits is odd. 11
1, 3, 5, 7, 9, 10, 12, 14, 16, 18, 21, 23, 25, 27, 29, 30, 32, 34, 36, 38, 41, 43, 45, 47, 49, 50, 52, 54, 56, 58, 61, 63, 65, 67, 69, 70, 72, 74, 76, 78, 81, 83, 85, 87, 89, 90, 92, 94, 96, 98, 100, 102, 104, 106, 108, 111, 113, 115, 117, 119, 120, 122, 124, 126, 128, 131 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Union of A179083 and A179085; A179081(a(n)) = 1. - Reinhard Zumkeller, Jun 28 2010

LINKS

R. Zumkeller, Table of n, a(n) for n = 1..1000

Index entries for 10-automatic sequences.

Index entries for Colombian or self numbers and related sequences

FORMULA

a(n) = n * 2 - 1 for the first 5 numbers; a(n) = n * 2 for the second 5 numbers.

From Robert Israel, Jun 27 2017: (Start)

a(n) = 2*n-2 if floor((n-1)/5) is in the sequence, 2*n-1 if not.

G.f. g(x) satisfies g(x) = (1-x)*(1+x+x^2+x^3+x^4)^2*g(x^10)/x^9 + x^2*(2+x^4+3*x^5-x^9+3*x^10)/((1-x)*(1+x^5))^2.

(End)

EXAMPLE

1, 3, 5, 7, 9, 10(1), 12(3), 14(5), 16(7), 18(9), 21(3) and so on.

MAPLE

[seq(`if`(convert(convert(2*n-1, base, 10), `+`)::odd, 2*n-1, 2*n-2), n=1..501)];

PROG

(PARI) is(n)=my(d=digits(n)); sum(i=1, #d, d[i])%2 \\ Charles R Greathouse IV, Aug 09 2013

CROSSREFS

Cf. A054683.

Sequence in context: A287774 A308412 A327254 * A294601 A080207 A187347

Adjacent sequences:  A054681 A054682 A054683 * A054685 A054686 A054687

KEYWORD

nonn,easy,base

AUTHOR

Odimar Fabeny, Apr 19 2000

EXTENSIONS

More terms from James A. Sellers, Apr 19 2000

STATUS

approved

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Last modified October 18 17:13 EDT 2019. Contains 328186 sequences. (Running on oeis4.)