A273863 The successive numbers of integers visible between two even terms are given by the sequence itself.

0, 2, 1, 3, 4, 5, 6, 7, 9, 11, 8, 13, 15, 17, 19, 10, 21, 23, 25, 27, 29, 12, 31, 33, 35, 37, 39, 41, 14, 43, 45, 47, 49, 51, 53, 55, 16, 57, 59, 61, 63, 65, 67, 69, 71, 73, 18, 75, 77, 79, 81, 83, 85, 87, 89, 91, 93, 95, 20, 97, 99, 101, 103, 105, 107, 109, 111, 22, 113, 115, 117, 119, 121, 123, 125, 127, 129, 131, 133, 135, 137, 24, 139, 141, 143, 145, 147, 149, 151, 153, 155, 157, 159, 161, 163, 165, 167, 26

Offset

1,2

Comments

The sequence starts with a(1)=0. It is then extended with the smallest integer not yet present and not leading to a contradiction. The sequence is a permutation of the integers >=0.

Links

Table of n, a(n) for n=1..98.

Example

The first two even terms that appear in the sequence are 0 and 2; between 0 and 2 there are 0 integers and this 0 corresponds to the starting 0 of the sequence.
The next even term is 4 and between 2 and 4 there are 2 integers [which are 1 and 3] and this 2 corresponds to the next term of the sequence.
The next even term is 6 and between 4 and 6 there is 1 integer [which is 5] and this 1 corresponds to the next term of the sequence.
The next even term is 8 and between 6 and 8 there are 3 integers [which are 7, 9 and 11] and this 3 corresponds to the next term of the sequence.
The next even term is 10 and between 8 and 10 there are 4 integers [which are 13, 15, 17 and 19] and this 4 corresponds to the next term of the sequence.
Etc.

Crossrefs

Sequence in context: A288118 A155963 A375326 * A273864 A058684 A226054

Adjacent sequences: A273860 A273861 A273862 * A273864 A273865 A273866

Keyword

nonn,base

Author

Eric Angelini, Jun 01 2016

Status

approved