cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-5 of 5 results.

A269369 a(1) = 1, a(n) = A260439(n)-th number k for which A260438(k) = A260438(n)+1; a(n) = A255551(A260438(n)+1, A260439(n)).

Original entry on oeis.org

1, 3, 7, 5, 19, 11, 9, 17, 13, 23, 39, 29, 15, 35, 21, 41, 61, 47, 27, 53, 25, 59, 81, 65, 31, 71, 45, 77, 103, 83, 33, 89, 37, 95, 123, 101, 43, 107, 57, 113, 145, 119, 49, 125, 55, 131, 165, 137, 51, 143, 63, 149, 187, 155, 85, 161, 97, 167, 207, 173, 91, 179, 67, 185, 229, 191, 69, 197, 73, 203, 249, 209, 75
Offset: 1

Views

Author

Antti Karttunen, Mar 01 2016

Keywords

Comments

For n > 1, a(n) = the number located immediately below n in A255551 (square array generated by Lucky sieve) in the same column where n itself is.
Permutation of odd numbers.

Crossrefs

Cf. A269370 (left inverse).
Cf. also A250469, A269379.

Programs

Formula

a(1) = 1; for n > 1, a(n) = A255551(A260438(n)+1, A260439(n)).
Other identities. For all n >= 1:
A269370(a(n)) = n.

A269387 Tree of Ludic sieve: a(0) = 1, a(1) = 2; after which, a(2n) = A269379(a(n)), a(2n+1) = 2*a(n).

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 9, 8, 7, 10, 15, 12, 19, 18, 21, 16, 11, 14, 27, 20, 35, 30, 33, 24, 31, 38, 51, 36, 49, 42, 45, 32, 13, 22, 39, 28, 65, 54, 57, 40, 59, 70, 87, 60, 79, 66, 69, 48, 55, 62, 111, 76, 125, 102, 105, 72, 85, 98, 123, 84, 109, 90, 93, 64, 17, 26, 63, 44, 95, 78, 81, 56, 113, 130, 159, 108, 139, 114, 117, 80
Offset: 0

Views

Author

Antti Karttunen, Mar 01 2016

Keywords

Comments

Permutation of natural numbers obtained from the Ludic sieve. Note the indexing: Domain starts from 0, range from 1.
This sequence can be represented as a binary tree. Each left hand child is obtained by applying A269379 to the parent's contents, and each right hand child is obtained by doubling the parent's contents:
1
|
...................2...................
3 4
5......../ \........6 9......../ \........8
/ \ / \ / \ / \
/ \ / \ / \ / \
/ \ / \ / \ / \
7 10 15 12 19 18 21 16
11 14 27 20 35 30 33 24 31 38 51 36 49 42 45 32
etc.
Sequence A269385 is obtained from the mirror image of the same tree.

Crossrefs

Inverse: A269388.
Cf. A003309 (left edge of the tree).
Cf. A269379.
Related permutations: A260741, A269171, A269385.
Cf. also A252753, A269377.

Formula

a(0) = 1, a(1) = 2; after which, a(2n) = A269379(a(n)), a(2n+1) = 2*a(n).
As a composition of other permutations:
a(n) = A269171(A252753(n)).
a(n) = A260741(A269377(n)).

A269375 Tree of Lucky sieve, mirrored: a(0) = 1, a(1) = 2; after which a(2n) = 2*a(n), a(2n+1) = A269369(a(n)).

Original entry on oeis.org

1, 2, 4, 3, 8, 5, 6, 7, 16, 17, 10, 19, 12, 11, 14, 9, 32, 41, 34, 61, 20, 23, 38, 27, 24, 29, 22, 39, 28, 35, 18, 13, 64, 89, 82, 145, 68, 95, 122, 91, 40, 53, 46, 81, 76, 107, 54, 45, 48, 65, 58, 103, 44, 59, 78, 57, 56, 77, 70, 123, 36, 47, 26, 15, 128, 185, 178, 313, 164, 239, 290, 217, 136, 197, 190, 333, 244, 359, 182, 147, 80
Offset: 0

Views

Author

Antti Karttunen, Mar 01 2016

Keywords

Comments

Permutation of natural numbers obtained from the Lucky sieve. Note the indexing: Domain starts from 0, range from 1.
This sequence can be represented as a binary tree. Each left hand child is obtained by doubling the parent's contents, and each right hand child is obtained by applying A269369 to the parent's contents:
1
|
...................2...................
4 3
8......../ \........5 6......../ \........7
/ \ / \ / \ / \
/ \ / \ / \ / \
/ \ / \ / \ / \
16 17 10 19 12 11 14 9
32 41 34 61 20 23 38 27 24 29 22 39 28 35 18 13
etc.
Sequence A269377 is obtained from the mirror image of the same tree.

Crossrefs

Inverse: A269376.
Cf. A000959 (with 2 inserted between 1 and 3 forms the right edge of the tree).
Related or similar permutations: A163511, A260742, A269377.
Cf. also A252755, A269385.

Formula

a(0) = 1, a(1) = 2; after which, a(2n) = 2*a(n), a(2n+1) = A269369(a(n)).
As a composition of related permutations:
a(n) = A260742(A269385(n)).
Other identities. For all n >= 2:
A000035(a(n)) = A000035(n). [This permutation preserves the parity of n from a(2)=4 onward.]

A269374 Permutation of natural numbers: a(1) = 1, a(n) = A255551(A001511(n), a(A003602(n))) - 1.

Original entry on oeis.org

1, 2, 3, 6, 5, 4, 11, 8, 9, 10, 7, 18, 21, 28, 15, 12, 17, 22, 19, 38, 13, 16, 35, 26, 41, 58, 55, 102, 29, 40, 23, 14, 33, 46, 43, 80, 37, 52, 75, 56, 25, 34, 31, 60, 69, 100, 51, 44, 81, 118, 115, 206, 109, 160, 203, 152, 57, 82, 79, 144, 45, 64, 27, 20, 65, 94, 91, 164, 85, 124, 159, 120, 73, 106, 103, 186, 149, 220, 111, 96, 49
Offset: 1

Views

Author

Antti Karttunen, Mar 01 2016

Keywords

Comments

Permutation obtained from the Lucky sieve.
This sequence can be represented as a binary tree. For n > 2, each left hand child is obtained by doubling the contents of the parent node and subtracting one, and each right hand child is obtained by applying A269372(n), when the parent node contains n:
1
|
...................2...................
3 6
5......../ \........4 11......../ \........8
/ \ / \ / \ / \
/ \ / \ / \ / \
/ \ / \ / \ / \
9 10 7 18 21 28 15 12
17 22 19 38 13 16 35 26 41 58 55 102 29 40 23 14
etc.

Crossrefs

Inverse: A269373.
Cf. also A269375, A269377 and also A249814, A269384.

Formula

a(1) = 1, a(n) = A255551(A001511(n), a(A003602(n))) - 1.
a(1) = 1, a(2n) = A269372(a(n)), a(2n+1) = (2*a(n+1))-1.
Other identities. For all n >= 0:
A000035(a(n)) = A000035(n). [This permutation preserves the parity of n.]

A269378 Permutation of natural numbers: a(1) = 0, after which a(2n) = 1 + 2*a(n), a(2n+1) = 2 * a(A269370(n)).

Original entry on oeis.org

0, 1, 2, 3, 6, 5, 4, 7, 8, 13, 10, 11, 16, 9, 32, 15, 14, 17, 12, 27, 64, 21, 26, 23, 128, 33, 24, 19, 22, 65, 256, 31, 512, 29, 18, 35, 1024, 25, 20, 55, 30, 129, 2048, 43, 48, 53, 34, 47, 4096, 257, 8192, 67, 54, 49, 96, 39, 40, 45, 42, 131, 28, 513, 16384, 63, 46, 1025, 32768, 59, 65536, 37, 66, 71, 131072, 2049, 262144, 51, 38, 41
Offset: 1

Views

Author

Antti Karttunen, Mar 01 2016

Keywords

Comments

Note the indexing: Domain starts from 1, range from 0.

Crossrefs

Inverse: A269377.
Cf. A269370.
Related permutation: A269376.
Cf. also A252754, A269388.

Formula

a(1) = 0, after which, a(2n) = 1 + 2*a(n), a(2n+1) = 2 * a(A269370(n)).
As a composition of related permutations:
a(n) = A269388(A260741(n)).
Showing 1-5 of 5 results.