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 A248381 Multiples of 3 in A247665 in order of appearance. 2
 9, 15, 27, 57, 81, 177, 243, 393, 579, 729, 849, 1257, 2187, 4197, 4143, 5853, 6561, 17817, 17781, 19683, 56157, 59049, 104289, 104277, 154509 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The initial multiples of 3 occur at positions 6,13,28,57,115,231, ... - conjecturally, for n > 13, A247665(n) is a multiple of 3 iff n = 29*2^k-1, k >= 0. LINKS EXAMPLE Table showing index where multiples of 3 appear, the multiple of 3, and the number of different prime factors of that term: 6 9 1 13 15 2 28 27 1 57 57 2 115 81 1 231 177 2 463 243 1 927 393 2 1855 579 2 3711 729 1 7423 849 2 14847 1257 2 29695 2187 1 59391 4197 2 118783 4143 2 237567 5853 2 475135 6561 1 950271 17817 2 1900543 17781 2 3801087 19683 1 7602175 56157 2 15204351 59049 1 30408703 104289 2 60817407 104277 2 121634815 154509 2 CROSSREFS Cf. A247665, A248379 (multiples of 2). Sequence in context: A258813 A046353 A046356 * A060874 A147511 A124580 Adjacent sequences:  A248378 A248379 A248380 * A248382 A248383 A248384 KEYWORD nonn,more AUTHOR Russ Cox and N. J. A. Sloane, Oct 12 2014 STATUS approved

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Last modified November 16 21:47 EST 2018. Contains 317275 sequences. (Running on oeis4.)