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 A257280 Inverse permutation of A139080 (a(n+1) = least unused m such that floor(max(m,a(n))/min(m,a(n))) = 2). 2
 1, 2, 5, 3, 8, 6, 11, 4, 16, 9, 14, 7, 19, 12, 24, 29, 34, 17, 22, 10, 27, 15, 32, 37, 42, 20, 47, 13, 52, 25, 57, 30, 40, 35, 45, 18, 50, 23, 55, 62, 67, 28, 60, 72, 77, 33, 82, 38, 87, 43, 92, 21, 97, 48, 65, 70, 102, 53, 75, 26, 80, 58, 85, 31, 107, 41, 90, 36, 95, 46, 100 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS A139080 was only conjectured to be a permutation, until a proof has been proposed recently. LINKS M. F. Hasler, Table of n, a(n) for n = 1..2500 PROG (PARI) A257280=vecsort(A=A139080, , 1); for(i=1, #A, A[A257280[i]]==i||return(A257280=A257280[1..i-1])) CROSSREFS Sequence in context: A191732 A197393 A257271 * A050171 A258406 A136189 Adjacent sequences:  A257277 A257278 A257279 * A257281 A257282 A257283 KEYWORD nonn AUTHOR M. F. Hasler, Apr 26 2015 STATUS approved

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Last modified January 22 23:00 EST 2019. Contains 319365 sequences. (Running on oeis4.)