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 A204458 Odd numbers not divisible by 17. 5
 1, 3, 5, 7, 9, 11, 13, 15, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 81, 83, 87, 89, 91, 93, 95, 97, 99, 101, 103, 105, 107, 109, 111, 113, 115, 117, 121, 123, 125, 127, 129, 131, 133, 135, 137, 139, 141 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS For the general case of odd numbers not divisible by a prime see a comment on A204454. There the o.g.f.s and the formulas are given. The numerator polynomial of the o.g.f. given below has coefficients 1,2,2,2,2,2,2,2,4,2,2,2,2,2,2,2,1. See the row no. 7 of the array A204456. The first nine numbers are the first differences of the sequence if one starts with a(0):=0. The remaining ones are obtained by mirroring around the central number 4. Compare with A192861: certain numbers from here are missing there, like 35, 49, 53, 71, 89, 97, 99, .. and others are missing here like 51, 85, 119, ... LINKS FORMULA O.g.f.: x*(1 + x^16 + 2*x*(1+x^8)*sum(x^k,k=0..6) + 4*x^8)/((1-x^16)*(1-x)). The denominator can be factored. a(n) = 2*n-1 + 2*floor((n+7)/16) = 2*n+1 + 2*floor((n-9)/16), n>=1. Note that for n=0 this is -1, but for the o.g.f. with start x^0 one uses a(0)=0. CROSSREFS Cf. A204454, also for more crossrefs. A204457. Sequence in context: A225563 A294923 A005842 * A192861 A192868 A283553 Adjacent sequences:  A204455 A204456 A204457 * A204459 A204460 A204461 KEYWORD nonn,easy AUTHOR Wolfdieter Lang, Feb 07 2012 STATUS approved

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Last modified February 23 05:58 EST 2019. Contains 320411 sequences. (Running on oeis4.)