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.

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A269855 a(0) = 1, a(1) = 2, after which, a(nth_odious_number_larger_than_one(n)) = A250469(a(n)), a(nth_evil_number_larger_than_zero(n)) = 2*a(n).

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 8, 9, 7, 10, 12, 15, 16, 21, 25, 18, 11, 14, 20, 27, 24, 33, 35, 30, 32, 45, 55, 42, 49, 50, 36, 51, 13, 22, 28, 39, 40, 57, 65, 54, 48, 69, 85, 66, 77, 70, 60, 87, 64, 93, 115, 90, 91, 110, 84, 123, 121, 98, 100, 147, 72, 105, 125, 102, 17, 26, 44, 63, 56, 81, 95, 78, 80, 117, 145, 114, 119, 130, 108, 159, 96
Offset: 0

Views

Author

Antti Karttunen, Mar 07 2016

Keywords

Comments

Permutation of natural numbers obtained from the sieve of Eratosthenes, combined with the inverse of Gray code. Note the indexing: Domain starts from 0, range from 1.

Links

Crossrefs

Inverse: A269856.
Cf. A000069, A001969, A010060, A115384, A245710, A250469.
Related or similar permutations: A006068, A252755, A269851.

Formula

a(0) = 1, a(1) = 2, for n > 1, if A010060(n) = 1 [when n is one of the odious numbers A000069], a(n) = A250469(a(A115384(n)-1)), otherwise [when n is one of the evil numbers A001969], a(n) = 2*a(A245710(n)).
As a composition of other permutations:
a(n) = A252755(A006068(n)).

A269857 Permutation of natural numbers: a(1) = 1; if n is an odd prime, a(n) = A250469(a(A026233(n))), else a(n) = 2*(a(A026233(n))).

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 9, 8, 10, 12, 7, 18, 15, 16, 20, 24, 25, 14, 21, 36, 30, 32, 27, 40, 48, 50, 28, 42, 33, 72, 11, 60, 64, 54, 80, 96, 51, 100, 56, 84, 35, 66, 45, 144, 22, 120, 57, 128, 108, 160, 192, 102, 69, 200, 112, 168, 70, 132, 49, 90, 39, 288, 44, 240, 114, 256, 55, 216, 320, 384, 105, 204, 87, 138, 400
Offset: 1

Views

Author

Antti Karttunen, Mar 06 2016

Keywords

Links

Crossrefs

Inverse: A269858.
Cf. A005843, A026233, A010051, A250469.
Related or similar permutations: A071574, A252755, A269847.
Differs from A269847 for the first time at n=19, where a(19)=21, while A269847(19)=27.

Formula

a(1) = 1; if n is an odd prime, a(n) = A250469(a(A026233(n))), else a(n) = 2*(a(A026233(n))).
As a composition of other permutations:
a(n) = A252755(A071574(n)).

A279348 a(1) = 1, for n > 1, if A079559(n) = 0, a(n) = 2*a(A256992(n)), otherwise a(n) = A250469(a(A256992(n))).

Original entry on oeis.org

1, 2, 3, 5, 4, 6, 7, 9, 10, 15, 11, 8, 12, 14, 25, 27, 18, 35, 13, 20, 30, 21, 33, 22, 39, 49, 16, 24, 28, 50, 65, 51, 54, 77, 17, 36, 70, 57, 87, 26, 55, 85, 40, 60, 42, 63, 95, 66, 121, 45, 44, 78, 69, 81, 98, 147, 119, 32, 48, 56, 100, 130, 125, 159, 102, 143, 19, 108, 154, 105, 207, 34, 145, 215, 72, 140, 114, 75, 91, 174, 133, 117, 52
Offset: 1

Views

Author

Antti Karttunen, Dec 12 2016

Keywords

Links

Crossrefs

Inverse: A279349.
Cf. A005187, A055938, A079559, A250469, A256992.
Related or similar permutations: A250245, A252753, A252755, A279338, A279341, A279343.

Programs

Formula

a(1) = 1, for n > 1, if A079559(n) = 0 [when n is a term of A055938], a(n) = 2*a(A256992(n)), otherwise a(n) = A250469(a(A256992(n))).
As a composition of other permutations:
a(n) = A250245(A279338(n)).
a(n) = A252753(A279343(n)).
a(n) = A252755(A279341(n)).
Previous Showing 21-23 of 23 results.

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