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A169748 A variation on Recamán's sequence A005132: see Comments for definition. 7
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, 59, 51, 42, 81, 71, 111, 70, 112, 69, 113, 68, 114, 67, 115, 66, 55, 43, 30, 80, 131, 79, 65, 50, 103, 49, 104 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Sequences A169748-A169752 have the same structure. We start with two sequences A and B. Sequence A is taken to be 1,2,3,4,5,6,7,..., while sequence B varies.

Here sequence B is also 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.

Finally, if that fails, we add the next term of A 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..70.

EXAMPLE

Start with 1 from A,

add 2 from A getting 3,

subtract 1 from B getting 2,

add 3 from A getting 5,

add 4 from A getting 9,

subtract 5 from A getting 4,

add 6 from A getting 10,

subtract 2 from B getting 8,

add 7 from A getting 15,

add 9 from A getting 16,

subtract 10 from A getting 6,

add 11 from A getting 17,

subtract 3 from B getting 14,

add 12 from A getting 26,

subtract 13 from A getting 13, ...

CROSSREFS

Cf. A005132, A169749-A169752, A169755.

Sequence in context: A081974 A257883 A169755 * A280875 A173701 A116627

Adjacent sequences:  A169745 A169746 A169747 * A169749 A169750 A169751

KEYWORD

nonn

AUTHOR

Rodolfo Kurchan, Apr 08 2010

EXTENSIONS

Extended by D. S. McNeil, May 09 2010

STATUS

approved

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Last modified May 14 16:48 EDT 2021. Contains 343898 sequences. (Running on oeis4.)