A143825 - OEIS

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A143825

This sequence displays every positive integer exactly three times; there is one number between the first and second 1's and one number between the second and third 1's; two numbers between the first and second 2's and two numbers between the second and third 2's; ... n numbers between the first and second n's and n numbers between the second and third n's.

1, 3, 1, 4, 1, 3, 5, 6, 4, 3, 8, 10, 5, 4, 6, 7, 9, 11, 5, 8, 13, 6, 10, 7, 2, 12, 9, 2, 8, 11, 2, 7, 14, 10, 13, 16, 9, 17, 12, 18, 15, 11, 20, 21, 22, 24, 19, 14, 13, 25, 23, 12, 16, 26, 27, 17, 15, 30, 18, 31, 28, 32, 14, 20, 34, 21, 19, 22, 33, 16, 24, 36, 15, 17, 23, 25, 35, 18, 37

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

The sequence displaying every positive integer exactly twice is A026272. Construction method: we always fill the next empty "hole" with the smallest available integer. There is no proof that this sequence could go on forever. Terms computed by Gilles Sadowski.

LINKS

Table of n, a(n) for n=1..79.

Eric Angelini, Kimberlike sequences

E. Angelini, Kimberlike sequences [Cached, with permission]

CROSSREFS

Sequence in context: A301848 A325610 A278536 * A290478 A240698 A010602

Adjacent sequences: A143822 A143823 A143824 * A143826 A143827 A143828

KEYWORD

base,nonn

AUTHOR

Eric Angelini, Sep 02 2008

STATUS

approved