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 A227413 a(1)=1, a(2n)=nthprime(a(n)), a(2n+1)=nthcomposite(a(n)), where nthprime = A000040, nthcomposite = A002808. 34
 1, 2, 4, 3, 6, 7, 9, 5, 8, 13, 12, 17, 14, 23, 16, 11, 10, 19, 15, 41, 22, 37, 21, 59, 27, 43, 24, 83, 35, 53, 26, 31, 20, 29, 18, 67, 30, 47, 25, 179, 58, 79, 34, 157, 54, 73, 33, 277, 82, 103, 40, 191, 62, 89, 36, 431, 114, 149, 51, 241, 75, 101, 39, 127, 46 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Inverse permutation of A135141. Shares with A073846 the property that the other bisection consists of just primes and the other bisection of just nonprimes. LINKS Antti Karttunen and Reinhard Zumkeller, Table of n, a(n) for n = 1..1000 FORMULA a(1)=1, a(2n) = A000040(a(n)), a(2n+1) = A002808(a(n)). A007097(n) = a(A000079(n)). PROG (Scheme, with Antti Karttunen's IntSeq-library) (definec (A227413 n) (cond ((< n 2) n) ((even? n) (A000040 (A227413 (/ n 2)))) (else (A002808 (A227413 (/ (- n 1) 2)))))) (Haskell) import Data.List (transpose) a227413 n = a227413_list !! (n-1) a227413_list = 1 : concat (transpose [map a000040 a227413_list,                                       map a002808 a227413_list]) -- Reinhard Zumkeller, Jan 29 2014 CROSSREFS Similarly constructed permutations: A227402, A227404, A227410, A227412. Cf. also A073846, A209636. Sequence in context: A246368 A316963 A006016 * A217122 A239622 A245604 Adjacent sequences:  A227410 A227411 A227412 * A227414 A227415 A227416 KEYWORD nonn,look AUTHOR Antti Karttunen, Jul 10 2013 STATUS approved

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Last modified October 19 16:00 EDT 2018. Contains 316365 sequences. (Running on oeis4.)