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 A334384 Lexicographically earliest sequence of distinct positive integers such that for any n > 0, a(3*n-2), a(3*n-1) and a(3*n) are in geometric progression. 2
 1, 2, 4, 3, 6, 12, 5, 10, 20, 7, 14, 28, 8, 16, 32, 9, 15, 25, 11, 22, 44, 13, 26, 52, 17, 34, 68, 18, 30, 50, 19, 38, 76, 21, 42, 84, 23, 46, 92, 24, 36, 54, 27, 45, 75, 29, 58, 116, 31, 62, 124, 33, 66, 132, 35, 70, 140, 37, 74, 148, 39, 78, 156, 40, 60, 90 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS This sequence is a permutation of the natural numbers. LINKS Rémy Sigrist, Table of n, a(n) for n = 1..9999 Rémy Sigrist, PARI program for A334384 EXAMPLE The first terms, alongside the corresponding common ratios, are:   n   a(3*n-2)  a(3*n-1)  a(3*n)  r   --  --------  --------  ------  ---    1         1         2       4    2    2         3         6      12    2    3         5        10      20    2    4         7        14      28    2    5         8        16      32    2    6         9        15      25  5/3    7        11        22      44    2    8        13        26      52    2    9        17        34      68    2   10        18        30      50  5/3   11        19        38      76    2   12        21        42      84    2   13        23        46      92    2   14        24        36      54  3/2   15        27        45      75  5/3 PROG (PARI) See Links section. CROSSREFS Cf. A334390. Sequence in context: A232564 A134561 A258046 * A225055 A341194 A120947 Adjacent sequences:  A334381 A334382 A334383 * A334385 A334386 A334387 KEYWORD nonn,look,tabf AUTHOR Rémy Sigrist, Apr 26 2020 STATUS approved

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Last modified April 20 20:26 EDT 2021. Contains 343137 sequences. (Running on oeis4.)