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 A164121 a(1)=1. a(n) = the smallest odd integer > a(n-1) such that a(n)*2 - a(n-1) is prime. 2
 1, 3, 5, 9, 11, 15, 17, 23, 27, 29, 33, 35, 39, 41, 47, 53, 57, 59, 63, 65, 69, 71, 75, 77, 83, 93, 95, 99, 101, 105, 107, 117, 127, 129, 133, 135, 137, 143, 147, 149, 153, 155, 159, 161, 167, 173, 177, 179, 185, 189, 191, 195, 197, 213, 221, 225, 227, 233, 237, 239 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Robert Israel, Table of n, a(n) for n = 1..10000 MAPLE R:= 1; x:= 1: count:= 1: for y from x+2 by 2 do if isprime(2*y-x) then R:= R, y; x:= y; count:= count+1; if count = 100 then break fi; fi od: R; # Robert Israel, Mar 22 2023 MATHEMATICA soi[a_]:=Module[{k=a+2}, While[!PrimeQ[2k-a], k=k+2]; k]; NestList[soi, 1, 60] (* Harvey P. Dale, Sep 02 2023 *) CROSSREFS Cf. A164122. Sequence in context: A040976 A268174 A166104 * A333171 A078651 A268732 Adjacent sequences: A164118 A164119 A164120 * A164122 A164123 A164124 KEYWORD nonn AUTHOR Leroy Quet, Aug 10 2009 EXTENSIONS More terms from R. J. Mathar, Oct 24 2009 STATUS approved

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Last modified September 17 19:20 EDT 2024. Contains 375990 sequences. (Running on oeis4.)