

A080032


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 even".


2



0, 2, 4, 1, 6, 7, 8, 10, 12, 11, 14, 16, 18, 15, 20, 22, 24, 19, 26, 28, 30, 23, 32, 34, 36, 27, 38, 40, 42, 31, 44, 46, 48, 35, 50, 52, 54, 39, 56, 58, 60, 43, 62, 64, 66, 47, 68, 70, 72, 51, 74, 76, 78, 55, 80, 82, 84, 59, 86, 88, 90, 63, 92, 94, 96, 67, 98, 100, 102, 71, 104
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OFFSET

0,2


COMMENTS

The same sequence, but without the initial 0, obeis the rule: "The concatenation of a(n) and a(a(n)) is even". Example: "2" and the 2nd term, concatenated, is 24; "4" and the 4th term, concatenated, is 46; "1" and the 1st term, concatenated, is 12; etc.  Eric Angelini, Feb 22 2017


LINKS

Table of n, a(n) for n=0..70.
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 >= 4 a(n) is given by: a(4m)=6m, a(4m+1)=4m+3, a(4m+2)=6m+2, a(4m+3)=6m+4.


CROSSREFS

Cf. A079000, A080029, A080030. Equals A079313  1.
Sequence in context: A128860 A019680 A249144 * A297121 A105357 A167546
Adjacent sequences: A080029 A080030 A080031 * A080033 A080034 A080035


KEYWORD

easy,nonn


AUTHOR

N. J. A. Sloane, Mar 14 2003


EXTENSIONS

More terms from Matthew Vandermast, Mar 21 2003


STATUS

approved



