A080633 a(1)=3; for n > 1, a(n) is the smallest integer greater than a(n-1) consistent with the condition "n is in the sequence if and only if a(n) is congruent to 1 (mod 4)".

3, 4, 5, 9, 13, 14, 15, 16, 17, 18, 19, 20, 21, 25, 29, 33, 37, 41, 45, 49, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 89, 93, 97, 101, 105, 109, 113, 117, 121, 125, 129, 133, 137, 141

Offset

1,1

Comments

Equivalently: unique monotonic sequence satisfying a(1)=3, a(a(n))=4n+1.

Links

Table of n, a(n) for n=1..67.

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

There is an explicit formula for a(n) similar to that for A079000.

Crossrefs

Sequence in context: A235396 A338256 A237132 * A360374 A242800 A136259

Adjacent sequences: A080630 A080631 A080632 * A080634 A080635 A080636

Keyword

nonn

Author

Benoit Cloitre, Feb 23 2003

Extensions

More terms from Matthew Vandermast, Mar 13 2003

Status

approved