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A088610 Starting with n = 1, a(n) is the smallest squarefree number not included earlier if n is odd, else n is the smallest nonsquarefree number. 5
1, 4, 2, 8, 3, 9, 5, 12, 6, 16, 7, 18, 10, 20, 11, 24, 13, 25, 14, 27, 15, 28, 17, 32, 19, 36, 21, 40, 22, 44, 23, 45, 26, 48, 29, 49, 30, 50, 31, 52, 33, 54, 34, 56, 35, 60, 37, 63, 38, 64, 39, 68, 41, 72, 42, 75, 43, 76, 46, 80, 47, 81, 51, 84, 53, 88, 55, 90, 57, 92, 58, 96 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

From Antti Karttunen, Jun 04 2014: (Start)

Squarefree (A005117) and nonsquarefree numbers (A013929) interleaved, the former at odd n and the latter at even n.

A243344 is a a "recursivized" variant of this permutation. Like this one, it also satisfies the given simple identity linking the parity of n with the Moebius mu-function.

(End).

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..8192

Index entries for sequences that are permutations of the natural numbers

FORMULA

From Antti Karttunen, Jun 04 2014: (Start)

a(2n) = A013929(n), a(2n-1) = A005117(n).

For all n, A008966(a(n)) = A000035(n), or equally, mu(a(n)) = n modulo 2, where mu is Moebius mu (A008683).

(End)

PROG

(Scheme) (define (A088610 n) (if (even? n) (A013929 (/ n 2)) (A005117 (/ (+ 1 n) 2))))

CROSSREFS

Inverse: A243352.

Bisections: A005117, A013929.

Similar permutations: A075378, A073846, A237056, A072061, A094077, A167151, A088609, A243344.

Sequence in context: A144926 A153016 A231549 * A026185 A026209 A198473

Adjacent sequences:  A088607 A088608 A088609 * A088611 A088612 A088613

KEYWORD

nonn

AUTHOR

Amarnath Murthy, Oct 16 2003

EXTENSIONS

More terms from Ray Chandler, Oct 18 2003

STATUS

approved

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Last modified February 24 17:29 EST 2020. Contains 332209 sequences. (Running on oeis4.)