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 A273493 a(n) =  A245327(n) + A245328(n). 3
 2, 3, 3, 5, 5, 4, 4, 8, 8, 7, 7, 7, 7, 5, 5, 13, 13, 11, 11, 12, 12, 9, 9, 11, 11, 10, 10, 9, 9, 6, 6, 21, 21, 18, 18, 19, 19, 14, 14, 19, 19, 17, 17, 16, 16, 11, 11, 18, 18, 15, 15, 17, 17, 13, 13, 14, 14, 13, 13, 11, 11, 7, 7, 34, 34, 29, 29, 31, 31, 23, 23, 30, 30, 27, 27, 25, 25, 17, 17, 31, 31, 26, 26, 29, 29, 22, 22, 25 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The terms (n>0) may be written as a left-justified array with rows of length 2^m, m >= 0: 2, 3, 3, 5, 5, 4, 4, 8, 8, 7, 7, 7, 7, 5, 5, 13,13,11,11,12,12, 9, 9,11,11,10,10, 9, 9, 6, 6, 21,21,18,18,19,19,14,14,19,19,17,17,16,16,11,11,18,18,15,15,17,17,13,13,14,14,... All columns have the Fibonacci sequence property: a(2^(m+2) + k) = a(2^(m+1) + k) + a(2^m + k), m >= 0,  0 <= k < 2^m (empirical observations). The terms (n>0) may also be written as a right-justified array with rows of length 2^m, m >= 0:                                                                               2,                                                                            3, 3,                                                                      5, 5, 4, 4,                                                          8, 8, 7, 7, 7, 7, 5, 5,                                 13,13,11,11,12,12, 9, 9,11,11,10,10, 9, 9, 6, 6,     ...,19,19,17,17,16,16,11,11,18,18,15,15,17,17,13,13,14,14,13,13,11,11, 7, 7, Each column is an arithmetic sequence. The differences of the arithmetic sequences repeat the sequence A071585: a(2^(m+2) -1 - 2k) - a(2^(m+1) -1 - 2k) = A071585(k-1),    m > 0,  0 ≤ k < 2^m ; a(2^(m+2) -1 - 2k - 1) - a(2^(m+1) -1 - 2k - 1) = A071585(k-1), m > 0,  0 ≤ k < 2^m . n>1 occurs in this sequence phi(n) = A000010(n) times, as it occurs in A007306 (Franklin T. Adams-Watters' comment), that is the sequence obtained by adding numerator and denominator in the Calkin-Wilf enumeration system of positive rationals. A245327(n)/A245328(n) is also an enumeration system of all positive rationals, and in each level m >= 0 (ranks between 2^m and 2^(m+1)-1) rationals are the same in both systems. Thus a(n) has the same terms in each level as A007306. a(n) = A273494(A059893(n)), a(A059893(n)) = A273494(n), n > 0. - Yosu Yurramendi, May 30 2017 LINKS CROSSREFS Cf. A007306, A268087, A071585, A086592, A273494 Sequence in context: A103310 A046146 A081768 * A193404 A072923 A257003 Adjacent sequences:  A273490 A273491 A273492 * A273494 A273495 A273496 KEYWORD nonn AUTHOR Yosu Yurramendi, May 23 2016 STATUS approved

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Last modified March 29 20:20 EDT 2020. Contains 333117 sequences. (Running on oeis4.)