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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 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.)