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Revision History for A341090 (Bold, blue-underlined text is an addition; faded, red-underlined text is a deletion.)

newer changes | Showing entries 11-16
Fully multiplicative: for any prime p, if the reversal of p in base 10, say q, is prime, then a(p) = q, otherwise a(p) = p.
(history; published version)
#6 by Michel Marcus at Sun Feb 13 11:13:07 EST 2022
STATUS

proposed

reviewed

#5 by Joerg Arndt at Sun Feb 13 10:52:05 EST 2022
STATUS

editing

proposed

#4 by Joerg Arndt at Sun Feb 13 10:52:00 EST 2022
NAME

Incrementally largest values of minimal y satisfying the equation x^2-D*y^2=6, where D is a prime number.

DATA

1, 5, 1877, 194255, 1730497, 45323015, 201492029, 397602538755575, 497108717282761, 7938459500809177705, 4015742266482169869985, 594448160241453500681390645, 1484161662562368548711372281538395, 2767866378797656254852541954053955, 504110847457236772029549084857628475205

OFFSET

1,2

LINKS

Christine Patterson, <a href="/A341090/a341090.txt">COCALC (Sage) Program</a>

EXAMPLE

For D=67, the least positive y for which x^2-D*y^2=6 has a solution is 5. The next prime, D, for which x^2-D*y^2=6 has a solution is 139, but the smallest positive y in this case is 5, which is equal to the previous record y. So, 139 is not a term.

The next prime, D, after 67 for which x^2-D*y^2=6 has a solution is 211 and the least positive y for which it has a solution is y=1877, which is larger than 5, so it is a new record y value. So, 67 qualifies for membership to sequence A341089 and 1877 qualifies for membership to this sequence.

As D runs through the primes, the minimal y values satisfying the equation x^2 - D*y^2 = 6 begin as follows:

y values satisfying minimal

D x^2 - D*y^2 = 6 y value record

-- --------------------- ------- ------

2 (none)

3 (none)

5 (none)

7 (none)

11 (none)

13 (none)

17 (none)

19 (none)

23 (none)

29 (none)

31 (none)

37 (none)

41 (none)

43 1, 235, 7199... 7 *

47 (none)

53 (none)

59 (none)

61 (none)

67 41, 3577, ... 41 *

The record high minimal values of y (marked with asterisks) are the terms of A341087. The corresponding values of D are the terms of this sequence. (End)

CROSSREFS
KEYWORD

nonn

recycled

AUTHOR

Christine Patterson, Feb 23 2021

#3 by Christine Patterson at Wed Apr 07 17:48:20 EDT 2021
EXAMPLE

As D runs through the primes, the minimal y values satisfying the equation x^2 - D*y^2 = 6 begin as follows:

y values satisfying minimal

D x^2 - D*y^2 = 6 y value record

-- --------------------- ------- ------

2 (none)

3 (none)

5 (none)

7 (none)

11 (none)

13 (none)

17 (none)

19 (none)

23 (none)

29 (none)

31 (none)

37 (none)

41 (none)

43 1, 235, 7199... 7 *

47 (none)

53 (none)

59 (none)

61 (none)

67 41, 3577, ... 41 *

The record high minimal values of y (marked with asterisks) are the terms of A341087. The corresponding values of D are the terms of this sequence. (End)

Discussion
Sat Feb 12
12:31
OEIS Server: This sequence has not been edited or commented on for a week
yet is not proposed for review.  If it is ready for review, please
visit https://oeis.org/draft/A341090 and click the button that reads
"These changes are ready for review by an OEIS Editor."

Thanks.
  - The OEIS Server
#2 by Christine Patterson at Tue Feb 23 14:25:06 EST 2021
NAME

allocated for Christine PattersonIncrementally largest values of minimal y satisfying the equation x^2-D*y^2=6, where D is a prime number.

DATA

1, 5, 1877, 194255, 1730497, 45323015, 201492029, 397602538755575, 497108717282761, 7938459500809177705, 4015742266482169869985, 594448160241453500681390645, 1484161662562368548711372281538395, 2767866378797656254852541954053955, 504110847457236772029549084857628475205

OFFSET

1,2

LINKS

Christine Patterson, <a href="/A341090/a341090.txt">COCALC (Sage) Program</a>

EXAMPLE

For D=67, the least positive y for which x^2-D*y^2=6 has a solution is 5. The next prime, D, for which x^2-D*y^2=6 has a solution is 139, but the smallest positive y in this case is 5, which is equal to the previous record y. So, 139 is not a term.

The next prime, D, after 67 for which x^2-D*y^2=6 has a solution is 211 and the least positive y for which it has a solution is y=1877, which is larger than 5, so it is a new record y value. So, 67 qualifies for membership to sequence A341089 and 1877 qualifies for membership to this sequence.

CROSSREFS
KEYWORD

allocated

nonn

AUTHOR

Christine Patterson, Feb 23 2021

STATUS

approved

editing

Discussion
Tue Apr 06
20:30
OEIS Server: This sequence has not been edited or commented on for a week
yet is not proposed for review.  If it is ready for review, please
visit https://oeis.org/draft/A341090 and click the button that reads
"These changes are ready for review by an OEIS Editor."

Thanks.
  - The OEIS Server
#1 by Christine Patterson at Thu Feb 04 18:32:01 EST 2021
NAME

allocated for Christine Patterson

KEYWORD

allocated

STATUS

approved