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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A257734 Permutation of natural numbers: a(1) = 1, a(lucky(n)) = ludic(1+a(n-1)), a(unlucky(n)) = nonludic(a(n)), where lucky(n) = n-th lucky number A000959, unlucky(n) = n-th unlucky number A050505, and ludic = A003309, nonludic = A192607.

Original entry on oeis.org

1, 4, 2, 9, 6, 16, 7, 12, 3, 26, 14, 20, 25, 8, 13, 38, 22, 31, 36, 15, 61, 21, 54, 33, 17, 45, 51, 24, 81, 32, 41, 73, 5, 48, 27, 62, 119, 69, 35, 105, 46, 57, 47, 96, 10, 65, 39, 82, 83, 151, 115, 92, 50, 135, 63, 76, 64, 124, 18, 86, 55, 106, 23, 108, 189, 146, 43, 118, 193, 68, 169, 84, 91, 100, 149, 85, 156, 28, 179, 111, 74, 136, 34
Offset: 1

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Author

Antti Karttunen, May 06 2015

Keywords

Crossrefs

Inverse: A257733.
Related or similar permutations: A237126, A255421, A257725, A257732.
Cf. also A256486, A256487.

Formula

a(1) = 1; for n > 1: if A145649(n) = 1 [i.e., if n is lucky], then a(n) = A003309(1+a(A109497(n)-1)), otherwise a(n) = A192607(a(n-A109497(n))).
As a composition of other permutations:
a(n) = A255421(A257732(n)).
a(n) = A237126(A257725(n)).

A266637 a(1) = 1; for n > 1, if A192490(2*n + 1) = 1 [when 2n+1 is a Ludic number] a(n) = A003309(1+a(A266350(n)-1)), otherwise a(n) = A192607(a(n-A266350(n))).

Original entry on oeis.org

1, 2, 3, 4, 5, 7, 6, 11, 8, 9, 17, 13, 10, 37, 14, 12, 19, 23, 15, 25, 67, 16, 43, 27, 21, 29, 18, 52, 22, 181, 20, 30, 47, 34, 41, 24, 36, 77, 88, 26, 97, 59, 39, 53, 115, 32, 42, 407, 28, 70, 33, 224, 61, 31, 44, 64, 227, 49, 121, 89, 57, 35, 131, 51, 71, 101, 113, 38, 125, 79, 287, 55, 72, 91, 146, 46, 58, 1361
Offset: 1

Views

Author

Antti Karttunen, Jan 28 2016

Keywords

Crossrefs

Inverse: A266638.
Related or similar permutations: A237126, A266417.

Formula

a(1) = 1; for n > 1, if A192490(2*n + 1) = 1 [when 2n+1 is Ludic number] a(n) = A003309(1+a(A266350(n)-1)), otherwise a(n) = A192607(a(n-A266350(n))).
As a composition of related permutations:
a(n) = A237126(A266417(n)).

A255420 Ludic recurrence: Iterates of f(n) = A003309(n+1) starting from n=1.

Original entry on oeis.org

1, 2, 3, 5, 11, 37, 181, 1361, 13927, 183871, 3005533, 59045717
Offset: 0

Views

Author

Antti Karttunen, Feb 23 2015

Keywords

Crossrefs

Programs

  • Haskell
    a255420 n = a255420_list !! n
    a255420_list = iterate (a003309 . (+ 1)) 1
    -- Reinhard Zumkeller, Feb 25 2015

Formula

a(0) = 1; for n >= 1: a(n) = A003309(1+a(n-1)).
Other identities. For all n >= 0:
a(n) = A237126(A000225(n+1)).
a(n) = A255421(A007097(n)).

A266419 Odd nonludic numbers.

Original entry on oeis.org

9, 15, 19, 21, 27, 31, 33, 35, 39, 45, 49, 51, 55, 57, 59, 63, 65, 69, 73, 75, 79, 81, 85, 87, 93, 95, 99, 101, 103, 105, 109, 111, 113, 117, 123, 125, 129, 133, 135, 137, 139, 141, 145, 147, 151, 153, 155, 159, 163, 165, 167, 169, 171, 177, 183, 185, 187, 189, 191, 195, 197, 199, 201, 203, 205, 207, 213, 215
Offset: 1

Views

Author

Antti Karttunen, Jan 28 2016

Keywords

Crossrefs

Intersection of A005408 and A192607.
Cf. also A071904, A266420.

Formula

Other identities. For all n >= 1:
a(n) = 1 + 2*A266410(n).
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