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.

A051420 Numbers k such that A000081(k) is prime.

Original entry on oeis.org

3, 10, 15, 343, 387, 1087, 2981, 96761
Offset: 1

Views

Author

David Broadhurst

Keywords

Comments

A000081(2981) = O(10^1400) is only a probably prime. No more terms < 6000.
No more terms < 40000. - Vaclav Kotesovec, Jul 07 2020
A000081(96761) is a probable prime. No other terms < 100000. - Mathieu Gouttenoire, Oct 08 2021

Crossrefs

Cf. A000081, A119642, A185667, A336039.

Extensions

a(8) from Mathieu Gouttenoire, Oct 08 2021

A119641 Prime numbers of trees with n unlabeled nodes.

Original entry on oeis.org

2, 3, 11, 23, 47, 1301, 7741, 83453838443384019701, 3497830604170469202903845457503189, 3043448204076362393100321053325760617159315927820231750001
Offset: 1

Views

Author

Jorge Coveiro, Jul 27 2006

Keywords

Crossrefs

Cf. A000055, A119642.

Formula

A000040 INTERSECTION A000055.
a(n) = A000055(A119642(n)). - Amiram Eldar, Apr 22 2018

Extensions

Offset changed by Michel Marcus, Apr 23 2018

A185667 Primes in A000081.

Original entry on oeis.org

2, 719, 87811
Offset: 1

Views

Author

Jonathan Vos Post, Feb 08 2011

Keywords

Comments

A000081(n) is prime for n in A051420.
a(4) = A000081(343) has 158 digits and is too large to be displayed here.

Links

Crossrefs

Cf. A000040, A000081, A005200, A051420, A119641, A119642.

Formula

A000040 INTERSECTION A000081.
a(n) = A000081(A051420(n)). - Amiram Eldar, Nov 11 2017

A336042 Numbers k such that A000055(k) is divisible by k.

Original entry on oeis.org

1, 6, 90, 1031, 1099
Offset: 1

Views

Author

Vaclav Kotesovec, Jul 08 2020

Keywords

Comments

No other terms below 40000.

Examples

			90 is in the sequence because A000055(90) = 90*179212383627255715871103677440244414

Crossrefs

Cf. A000055, A051420, A119642, A336039.
Showing 1-4 of 4 results.

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

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