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 A162600 a(n) = the smallest integer > n that has yet to occur in the sequence, and that is not coprime to n. 0
 4, 6, 8, 10, 9, 14, 12, 15, 16, 22, 18, 26, 20, 21, 24, 34, 27, 38, 25, 28, 30, 46, 32, 35, 36, 33, 40, 58, 39, 62, 42, 44, 48, 45, 50, 74, 52, 51, 54, 82, 49, 86, 55, 57, 56, 94, 60, 63, 64, 66, 65, 106, 68, 70, 72, 69, 76, 118, 75, 122, 78, 77, 80, 85, 81, 134, 84, 87, 88, 142 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,1 COMMENTS Is this a permutation of the composite integers? LINKS MATHEMATICA g[n_] := g[n] = Block[{k = n + 1, t = Table[ g@i, {i, 2, n - 1}]}, While[ MemberQ[t, k] || GCD[n, k] == 1, k++ ]; k]; Table[ g@n, {n, 2, 71}] (* or *) f[lst_] := Block[{len = 2 + Length@lst}, k = 1 + len; While[ MemberQ[lst, k] || GCD[len, k] == 1, k++ ]; Append[lst, k]]; Nest[f, {}, 70] (* Robert G. Wilson v, Aug 17 2009 *) CROSSREFS Sequence in context: A277514 A331208 A191488 * A071537 A161396 A145256 Adjacent sequences:  A162597 A162598 A162599 * A162601 A162602 A162603 KEYWORD nonn AUTHOR Leroy Quet, Jul 07 2009 EXTENSIONS a(17) and further terms from Robert G. Wilson v, Aug 17 2009 STATUS approved

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Last modified April 21 14:38 EDT 2021. Contains 343154 sequences. (Running on oeis4.)