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 A257314 a(1) = 18; a(2) = 19; for n > 2, a(n) is the smallest number of the form prime + 16 not already used which shares a factor with a(n-1). 5
 18, 19, 57, 21, 27, 33, 39, 45, 35, 63, 69, 23, 207, 75, 87, 29, 435, 95, 105, 77, 99, 117, 123, 129, 147, 119, 153, 165, 125, 155, 195, 143, 209, 285, 183, 189, 213, 243, 249, 83, 1079, 273, 245, 215, 255, 267, 89, 623, 287, 329, 47, 893, 323, 399, 279, 297 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Analog of EKG-sequence (A064413) on the numbers of the form prime + 16. Conjecture: the sequence {a(n)-16} is a permutation of primes (A000040). LINKS Peter J. C. Moses, Table of n, a(n) for n = 1..1000 MATHEMATICA f[n_] := Block[{o = 16, s, p, k}, s = {o + 2, o + 3}; For[k = 3, k <= n, k++, p = 2; While[GCD[p + o, s[[k - 1]]] == 1 || MemberQ[s, p + o], p = NextPrime@ p]; AppendTo[s, p + o]]; s]; f@ 56 (* Michael De Vlieger, Apr 20 2015 *) CROSSREFS Cf. A000040, A064413, A257311, A257312, A257313, A257315. Sequence in context: A300092 A042517 A041660 * A041668 A041666 A041670 Adjacent sequences:  A257311 A257312 A257313 * A257315 A257316 A257317 KEYWORD nonn AUTHOR Vladimir Shevelev, Apr 20 2015 EXTENSIONS More terms from Peter J. C. Moses, Apr 20 2015 STATUS approved

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Last modified October 21 19:19 EDT 2019. Contains 328308 sequences. (Running on oeis4.)