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 1-4 of 4 results.

A266409 a(n) = (A003309(n+2)-1) / 2; numbers n such that 2n+1 is a Ludic number (in A003309).

Original entry on oeis.org

1, 2, 3, 5, 6, 8, 11, 12, 14, 18, 20, 21, 23, 26, 30, 33, 35, 38, 41, 44, 45, 48, 53, 57, 59, 60, 63, 65, 71, 74, 78, 80, 86, 87, 89, 90, 96, 104, 105, 110, 111, 113, 116, 117, 119, 123, 128, 132, 138, 141, 143, 150, 153, 156, 164, 165, 168, 170, 176, 179, 180, 188, 191, 194, 198, 203, 207, 209, 210, 215
Offset: 1

Views

Author

Antti Karttunen, Jan 28 2016

Keywords

Comments

Ludic numbers from A003309(2) = 3 onward, decremented by one, then halved.

Links

Crossrefs

Complement: A266410.
Cf. A003309, A192490.
Cf. A266350 (least monotonic left inverse).
Cf. permutations A266418, A266638.
Cf. also A005097.

Formula

a(n) = (A003309(n+2)-1) / 2.
Other identities. For all n >= 1:
A266350(a(n)) = n.

A266410 a(n) = (A266419(n) - 1) / 2; numbers n such that 2n+1 is a nonludic number (in A192607).

Original entry on oeis.org

4, 7, 9, 10, 13, 15, 16, 17, 19, 22, 24, 25, 27, 28, 29, 31, 32, 34, 36, 37, 39, 40, 42, 43, 46, 47, 49, 50, 51, 52, 54, 55, 56, 58, 61, 62, 64, 66, 67, 68, 69, 70, 72, 73, 75, 76, 77, 79, 81, 82, 83, 84, 85, 88, 91, 92, 93, 94, 95, 97, 98, 99, 100, 101, 102, 103, 106, 107, 108, 109, 112, 114, 115, 118, 120, 121
Offset: 1

Views

Author

Antti Karttunen, Jan 28 2016

Keywords

Comments

Odd nonludic numbers (A266419) decremented by one, then halved.

Links

Crossrefs

Complement: A266409.
Cf. A192490, A192607, A266419.
Cf. permutations A266418, A266638.
Cf. also A047845.

Formula

a(n) = (A266419(n) - 1) / 2.

A266638 a(1) = 1, a(ludic(n)) = (ludic(3+a(n-1))-1)/2, a(nonludic(n)) = A266410(a(n)), where ludic(n) = n-th ludic number A003309, nonludic(n) = n-th nonludic number A192607 and A266410 = numbers n such that 2n+1 is nonludic.

Original entry on oeis.org

1, 2, 3, 4, 5, 7, 6, 9, 10, 13, 8, 16, 12, 15, 19, 22, 11, 27, 17, 31, 25, 29, 18, 36, 20, 40, 24, 49, 26, 32, 54, 46, 51, 34, 62, 37, 14, 68, 43, 81, 35, 47, 23, 55, 88, 76, 33, 83, 58, 99, 64, 28, 44, 107, 72, 127, 61, 77, 42, 91, 53, 136, 121, 56, 130, 94, 21, 151, 101, 50, 65, 73, 161, 114, 189, 98, 38
Offset: 1

Views

Author

Antti Karttunen, Jan 28 2016

Keywords

Links

Crossrefs

Inverse: A266637.
Cf. A003309, A192490, A192512, A236863, A266409, A266410.
Related or similar permutations: A237427, A266418.

Formula

a(1) = 1; for n > 1, if A192490(n) = 1 [when n is one of Ludic numbers, A003309] a(n) = A266409(1+a(A192512(n)-1)), otherwise a(n) = A266410(a(A236863(n))).
As a composition of related permutations:
a(n) = A266418(A237427(n)).

A266417 a(1) = 1; for n > 1, if A192490(2n+1) = 1 [when 2n+1 is Ludic number] a(n) = 1 + 2*a(A266350(n)-1), otherwise a(n) = 2*a(n-A266350(n)).

Original entry on oeis.org

1, 3, 7, 2, 15, 5, 6, 31, 14, 4, 11, 13, 30, 63, 10, 12, 62, 29, 28, 9, 23, 8, 27, 22, 26, 61, 60, 126, 20, 127, 24, 124, 21, 58, 25, 56, 18, 125, 46, 16, 59, 54, 44, 57, 19, 52, 122, 47, 120, 252, 40, 254, 17, 48, 248, 42, 55, 116, 45, 53, 50, 112, 123, 36, 121, 250, 92, 32, 118, 108, 253, 88, 114, 41, 38
Offset: 1

Views

Author

Antti Karttunen, Jan 28 2016

Keywords

Links

Crossrefs

Inverse: A266418.
Cf. A003309, A192607, A192490, A266350.
Similar or related permutations: A237427, A266637.

Formula

a(1) = 1; for n > 1, if A192490(2*n + 1) = 1 [when 2n+1 is Ludic number] a(n) = 1 + 2*a(A266350(n)-1), otherwise a(n) = 2*a(n-A266350(n)).
As a composition of related permutations:
a(n) = A237427(A266637(n)).
Showing 1-4 of 4 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement.