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 1-3 of 3 results.

A128472 a(n) is the smallest prime of the form (2n-1)^k - 2 for k > (2n-1), or 0 if no such number exists.

Original entry on oeis.org

0, 79, 6103515623, 5764799, 31381059607
Offset: 1

Views

Author

Alexander Adamchuk, Mar 14 2007, Oct 01 2007

Keywords

Comments

a(6) = 11^22420 - 2 was found by Rick L. Shepherd on Sep 29 2007. It has 23349 decimal digits and it is too large to include.
a(7) through a(12): {771936328432730777189183517369830159827426282764863750131729657829597399846468418688727, 98526125335693359373, 339448671314611904643504117119, 37589973457545958193355599, 1136272165922724266740722458520499, 480250763996501976790165756943039}.

Links

Crossrefs

Cf. A084714 (smallest prime of the form (2n-1)^k - 2).
Cf. A133856 (least number k > (2n-1) such that (2n-1)^k - 2 is prime).
Cf. A014224, A109080, A090669, A128455, A128457, A128458, A128459, A128460, A128461.
Cf. A133858, A133982.

Extensions

Edited by Max Alekseyev, Sep 18 2009

A133982 Numbers n such that 11^n - 2 is prime.

Original entry on oeis.org

4, 6, 22420, 27636, 27850, 28986, 31168, 586020
Offset: 1

Views

Author

Rick L. Shepherd, Sep 30 2007

Keywords

Comments

Corresponding primes are in A133858.
11^22420-2 is a 23349-digit probable prime found with PrimeForm.
a(8) > 10^5. - Robert Price, Mar 26 2014
a(4) through a(7) also correspond to probable primes. - Robert Price, Mar 27 2014

Crossrefs

Cf. A133858, A130652.

Programs

Extensions

a(4)-a(7) from Robert Price, Mar 26 2014
a(8) from Paul Bourdelais, Nov 03 2021

A133856 Least number k > (2n-1) such that (2n-1)^k - 2 is prime, or 0 if no such number exists.

Original entry on oeis.org

0, 4, 14, 8, 11, 22420, 78, 17, 24, 20, 25, 24, 63, 30, 42, 69, 128, 50, 119, 204, 2816, 76, 52, 288, 64, 66, 184, 153, 67, 268, 78, 210, 438, 295, 96, 74, 136, 128, 2900, 1898, 130, 92, 381, 106, 18626, 97, 98, 1650, 747, 109, 214, 113, 312, 354, 1702, 560, 2798, 123, 171, 554, 11210, 834, 208, 990, 9271
Offset: 1

Views

Author

Alexander Adamchuk, Oct 01 2007

Keywords

Comments

a(66) > 40000. - Robert Price, Mar 02 2015

Links

Crossrefs

Cf. A128472 (smallest prime of the form (2n-1)^k - 2 for k > (2n-1), or 0 if no such number exists).
Cf. A084714 (smallest prime of the form (2n-1)^k - 2, or 0 if no such number exists).
Cf. A014224, A109080, A090669, A128455, A128457, A128458, A128459, A128460, A128461.
Cf. A133858, A133982.

Formula

A128472(n) = (2n-1)^a(n) - 2 for n > 1.

Extensions

a(6) = 22420 was found by Rick L. Shepherd, Sep 29 2009
a(21)-a(44) from Max Alekseyev, Oct 04 2007
a(45)-a(65) from Robert Price, Mar 02 2015
Showing 1-3 of 3 results.

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

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