# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a334384 Showing 1-1 of 1 %I A334384 #10 May 03 2020 13:49:46 %S A334384 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, %T A334384 68,18,30,50,19,38,76,21,42,84,23,46,92,24,36,54,27,45,75,29,58,116, %U A334384 31,62,124,33,66,132,35,70,140,37,74,148,39,78,156,40,60,90 %N 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. %C A334384 This sequence is a permutation of the natural numbers. %H A334384 Rémy Sigrist, Table of n, a(n) for n = 1..9999 %H A334384 Index entries for sequences that are permutations of the natural numbers %H A334384 Rémy Sigrist, PARI program for A334384 %e A334384 The first terms, alongside the corresponding common ratios, are: %e A334384 n a(3*n-2) a(3*n-1) a(3*n) r %e A334384 -- -------- -------- ------ --- %e A334384 1 1 2 4 2 %e A334384 2 3 6 12 2 %e A334384 3 5 10 20 2 %e A334384 4 7 14 28 2 %e A334384 5 8 16 32 2 %e A334384 6 9 15 25 5/3 %e A334384 7 11 22 44 2 %e A334384 8 13 26 52 2 %e A334384 9 17 34 68 2 %e A334384 10 18 30 50 5/3 %e A334384 11 19 38 76 2 %e A334384 12 21 42 84 2 %e A334384 13 23 46 92 2 %e A334384 14 24 36 54 3/2 %e A334384 15 27 45 75 5/3 %o A334384 (PARI) See Links section. %Y A334384 Cf. A334390. %K A334384 nonn,look,tabf %O A334384 1,2 %A A334384 _Rémy Sigrist_, Apr 26 2020 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE