

A079313


a(n) is taken to be the smallest positive integer not already present which is consistent with the condition "n is a member of the sequence if and only if a(n) is odd".


7



1, 3, 5, 2, 7, 8, 9, 11, 13, 12, 15, 17, 19, 16, 21, 23, 25, 20, 27, 29, 31, 24, 33, 35, 37, 28, 39, 41, 43, 32, 45, 47, 49, 36, 51, 53, 55, 40, 57, 59, 61, 44, 63, 65, 67, 48, 69, 71, 73, 52, 75, 77, 79, 56, 81, 83, 85, 60, 87, 89, 91, 64, 93, 95, 97, 68, 99, 101, 103, 72, 105
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OFFSET

1,2


COMMENTS

The sequence obeys the rule: "The concatenation of a(n) and a(a(n)) is odd". Example: "1" and the 1st term, concatenated, is 11; "3" and the 3rd term, concatenated, is 35; "5" and the 5th term, concatenated, is 57; "2" and the 2nd term, concatenated, is 23; etc.


LINKS

Table of n, a(n) for n=1..71.
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, arXiv:math/0305308 [math.NT], 2003.


FORMULA

For n >= 5 a(n) is given by: a(4t2) = 4t, a(4t1) = 6t3, a(4t) = 6t1, a(4t+1) = 6t+1.
All odd numbers occur; the only even numbers which occur are 2 and the multiples of 4 excluding 4 itself.


CROSSREFS

Equals A080032 + 1. Cf. A079000, A079250A079259, A080029A080031.
Sequence in context: A210042 A338872 A274421 * A125132 A243352 A026184
Adjacent sequences: A079310 A079311 A079312 * A079314 A079315 A079316


KEYWORD

easy,nonn


AUTHOR

J. C. Lagarias and N. J. A. Sloane, Feb 11 2003


EXTENSIONS

More terms from Matthew Vandermast, Mar 20 2003


STATUS

approved



