

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
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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 memoizationmacro 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



