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 A277330 a(0)=1, a(1)=2, a(2n) = A003961(a(n)), a(2n+1) = lcm(a(n),a(n+1))/gcd(a(n),a(n+1)). 12
 1, 2, 3, 6, 5, 2, 15, 30, 7, 10, 3, 30, 35, 2, 105, 210, 11, 70, 21, 30, 5, 10, 105, 42, 77, 70, 3, 210, 385, 2, 1155, 2310, 13, 770, 231, 30, 55, 70, 105, 6, 7, 2, 21, 42, 385, 10, 165, 66, 143, 110, 231, 210, 5, 70, 1155, 66, 1001, 770, 3, 2310, 5005, 2, 15015, 30030, 17, 10010, 3003, 30, 715, 770, 105, 66, 91, 154, 231, 6, 385, 70, 15, 42, 11, 14, 3, 42, 55, 2 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Each term is a squarefree number, A005117. LINKS Antti Karttunen, Table of n, a(n) for n = 0..8191 FORMULA a(0) = 1, a(1) = 2, a(2n) = A003961(a(n)), a(2n+1) = lcm(a(n),a(n+1))/gcd(a(n),a(n+1)). Other identities. For all n >= 0: a(n) = A007913(A260443(n)). a(n) = A019565(A264977(n)), A048675(a(n)) = A264977(n). A055396(a(n)) = A277707(A260443(n)) = A001511(n). PROG (Scheme, with memoization-macro definec) (definec (A277330 n) (cond ((<= n 1) (+ 1 n)) ((even? n) (A003961 (A277330 (/ n 2)))) (else (/ (lcm (A277330 (/ (- n 1) 2)) (A277330 (/ (+ n 1) 2))) (gcd (A277330 (/ (- n 1) 2)) (A277330 (/ (+ n 1) 2))))))) CROSSREFS Cf. A001511, A003961, A005117, A007913, A019565, A048675, A055396, A260443, A264977, A277707. Cf. A023758 (positions where coincides with A260443). Cf. A277701, A277712, A277713 for the positions of 2's, 3's and 6's in this sequence, which are also the first three rows of array A277710. Cf. also A255483. Sequence in context: A011159 A091556 A299207 * A072298 A130686 A213927 Adjacent sequences:  A277327 A277328 A277329 * A277331 A277332 A277333 KEYWORD nonn AUTHOR Antti Karttunen, Oct 27 2016 STATUS approved

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Last modified October 18 08:08 EDT 2019. Contains 328146 sequences. (Running on oeis4.)