A080588 a(n) is smallest nonnegative integer which is consistent with sequence being monotonically increasing and satisfying a(a(n)) = 4n.

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

Offset

0,2

Comments

Equivalently: a(n) is taken to be the smallest positive integer greater than a(n-1) 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.

Links

Mathieu Gouttenoire, Table of n, a(n) for n = 0..100000

J.-P. Allouche, N. Rampersad and J. Shallit, On integer sequences whose first iterates are linear, Aequationes Math. 69 (2005), 114-127.

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.

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(n-1) + 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