OFFSET
1,2
COMMENTS
This sequence is a permutation of the positive integers with inverse A355436.
The construction of this sequence is similar to that of A269838.
This sequence can also be seen as an irregular table:
- with row lengths given by A011782,
- with initial row (1),
- given the first k+1 rows (with globally 2^k terms), the next row contains a multiple of a(2^k), followed by a multiple of a(2^k-1), ..., followed by a multiple of a(1).
LINKS
Rémy Sigrist, Table of n, a(n) for n = 1..8192
Rémy Sigrist, PARI program
FORMULA
a(2^n) = prime(n) for any n > 0 (where prime(n) denotes the n-th prime number).
EXAMPLE
As an irregular table, the first rows are:
[1]
[2]
[4, 3]
[6, 8, 10, 5]
[15, 20, 16, 12, 9, 24, 14, 7]
[21, 28, 48, 18, 36, 32, 40, 30, 25, 50, 56, 42, 27, 44, 22, 11]
.
The first terms are:
-- ---- ------------ ---------------
1 1 N/A N/A
2 2 1 1
3 4 2 2
4 3 1 1
5 6 4 3
6 8 3 4
7 10 2 2
8 5 1 1
9 15 8 5
10 20 7 10
11 16 6 8
12 12 5 6
13 9 4 3
14 24 3 4
15 14 2 2
16 7 1 1
PROG
(PARI) See Links section.
CROSSREFS
KEYWORD
nonn,tabf
AUTHOR
Rémy Sigrist, Jul 02 2022
STATUS
approved