

A080588


a(n) is smallest nonnegative integer which is consistent with sequence being monotonically increasing and satisfying a(a(n)) = 4n.


3



0, 2, 4, 5, 8, 12, 13, 14, 16, 17, 18, 19, 20, 24, 28, 29, 32, 36, 40, 44, 48, 49, 50, 51, 52, 53, 54, 55, 56, 60, 61, 62, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 84, 88, 92, 96, 100, 104, 108, 112, 113, 114, 115, 116, 120, 124, 125
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OFFSET

0,2


COMMENTS

Equivalently: a(n) is taken to be the smallest positive integer greater than a(n1) which is consistent with the condition "n is a member of the sequence if and only if a(n) is a multiple of 4".
The sequence of even numbers shares many of the properties of this sequence.


REFERENCES

J.P. Allouche, N. Rampersad and J. Shallit, On integer sequences whose first iterates are linear, Aequationes Math. 69 (2005), 114127


LINKS

Table of n, a(n) for n=0..63.
B. Cloitre, N. J. A. Sloane and M. J. Vandermast, Numerical analogues of Aronson's sequence, J. Integer Seqs., Vol. 6 (2003), #03.2.2.
B. Cloitre, N. J. A. Sloane and M. J. Vandermast, Numerical analogues of Aronson's sequence (math.NT/0305308)
Index entries for sequences of the a(a(n)) = 2n family


FORMULA

a(a(n)) = 4n. a(2^k) = 2^(k+1).


CROSSREFS

a(n) = A080591(n1) + 1, n >= 1. Cf. A079000, A080591, A080589.
Sequence in context: A080136 A080033 A007379 * A032850 A190190 A063465
Adjacent sequences: A080585 A080586 A080587 * A080589 A080590 A080591


KEYWORD

nonn,easy,nice


AUTHOR

N. J. A. Sloane, Feb 23 2003


STATUS

approved



