A379692 a(1) = 1; a(n) is the most recently occurring value not among the last k terms where k is the number of times a(n-1) has occurred; if no such value exists, a(n) is the smallest unused positive integer.

1, 2, 1, 3, 1, 2, 3, 1, 4, 1, 5, 1, 2, 4, 1, 3, 2, 5, 3, 1, 6, 1, 7, 1, 4, 6, 1, 8, 1, 2, 4, 6, 1, 3, 8, 1, 5, 3, 6, 8, 5, 1, 7, 5, 6, 8, 1, 4, 7, 8, 6, 5, 3, 2, 4, 7, 5, 8, 6, 1, 9, 1, 10, 1, 11, 1, 12, 1, 13, 1, 14, 1, 15, 1, 16, 1, 17, 1, 18, 1, 3, 15, 1, 4

Offset

1,2

Comments

The number preceding and following each first occurrence is the same (with the exception of a(1)=1 which has no predecessor).

Links

Neal Gersh Tolunsky, Table of n, a(n) for n = 1..10000

Neal Gersh Tolunsky, Graph of 100000 terms

Neal Gersh Tolunsky, Ordinal transform of 200000 terms

Neal Gersh Tolunsky, Graph of 400000 terms

Example

To find a(14)=4, we see that a(13) = 2 has occurred 3 times in the sequence, so the most recently occurring value before (5, 1, 2) which is not equal to 5,1,2 is a(9) = 4, so a(14) = 4.

Crossrefs

Cf. A358921.

Sequence in context: A132662 A279782 A358921 * A390101 A132589 A054843

Adjacent sequences: A379689 A379690 A379691 * A379693 A379694 A379695

Keyword

nonn

Author

Neal Gersh Tolunsky, Dec 29 2024

Status

approved