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 A260439 Column index to A255551: a(1) = 0; for n > 1: if n is Lucky number then a(n) = 1, otherwise for a(2k) = k, and for odd unlucky numbers, a(n) = 1 + the position at the stage where n is removed in the Lucky sieve. 9
 0, 1, 1, 2, 2, 3, 1, 4, 1, 5, 3, 6, 1, 7, 1, 8, 4, 9, 2, 10, 1, 11, 5, 12, 1, 13, 2, 14, 6, 15, 1, 16, 1, 17, 7, 18, 1, 19, 3, 20, 8, 21, 1, 22, 2, 23, 9, 24, 1, 25, 1, 26, 10, 27, 2, 28, 3, 29, 11, 30, 4, 31, 1, 32, 12, 33, 1, 34, 1, 35, 13, 36, 1, 37, 1, 38, 14, 39, 1, 40, 5, 41, 15, 42, 2, 43, 1, 44, 16, 45, 4, 46, 1, 47, 17, 48, 3, 49, 1, 50, 18, 51, 6, 52, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS a(1) = 0, because 1 is outside of A255551 array proper. LINKS Antti Karttunen, Table of n, a(n) for n = 1..10003 FORMULA Other identities. For all n >= 1: a(2n) = n. Also, for all n >= 2: A255551(A260438(n), a(n)) = n. a(A219178(n)) = 2. PROG (Scheme) (define (A260439 n) (cond ((= 1 n) 0) ((not (zero? (A145649 n))) 1) ((even? n) (/ n 2)) (else (let searchrow ((row 2)) (let searchcol ((col 1)) (cond ((>= (A255543bi row col) n) (if (= (A255543bi row col) n) (+ 1 col) (searchrow (+ 1 row)))) (else (searchcol (+ 1 col))))))))) ;; Code for A255543bi given in A255543. CROSSREFS Cf. A000959, A050505, A145649, A255543, A255551. Cf. also A260438 (corresponding row index). Cf. A078898, A246277, A260429, A260437, A260739 for column indices to other arrays similar to A255551. Sequence in context: A322025 A072078 A322316 * A182471 A078378 A141197 Adjacent sequences:  A260436 A260437 A260438 * A260440 A260441 A260442 KEYWORD nonn AUTHOR Antti Karttunen, Jul 29 2015 STATUS approved

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Last modified August 20 06:04 EDT 2019. Contains 326139 sequences. (Running on oeis4.)