A169755 A variation on Recamán's sequence A005132: see Comments for definition.

1, 3, 2, 5, 9, 4, 10, 8, 15, 7, 16, 6, 17, 14, 26, 13, 27, 12, 28, 11, 29, 25, 20, 39, 19, 40, 18, 41, 35, 59, 34, 60, 33, 61, 32, 62, 31, 24, 56, 23, 57, 22, 58, 21, 29, 67, 106, 66, 107, 65, 108, 64, 55, 45, 90, 44, 91, 43, 92, 42, 93, 82, 30, 83, 71, 125, 70, 126, 69, 127, 68

Offset

1,2

Comments

We start with two sequences A and B. Here sequences A and B are both taken to be 1,2,3,4,5,6,7,....

We start with the first term of sequence A (which is 1).

To extend the sequence, we first try to subtract the next term of A from the current term, but that is allowed only if the result is a positive number not already in the sequence.

If that fails, we next try to subtract the next term of B from the current term, but again that is allowed only if the result is a positive number not already in the sequence.

If that fails, we next try to add the next term of A to the current term, but again that is allowed only if the result is a positive number not already in the sequence.

Finally, if that fails, we add the next term of B to the current term (this may produce repeated terms, but that is allowed at this step).

Links

Table of n, a(n) for n=1..71.

Crossrefs

Cf. A005132, A169748-A169752.

Sequence in context: A278743 A081974 A257883 * A169748 A280875 A173701

Adjacent sequences: A169752 A169753 A169754 * A169756 A169757 A169758

Keyword

nonn

Author

Rodolfo Kurchan, Apr 08 2010

Extensions

Corrected and extended by D. S. McNeil, May 09 2010

Status

approved