The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A178998 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
Showing entries 1-10 | older changes

A178998

Primes of the form 4^k mod 3^k.
(history; published version)

#22 by Sean A. Irvine at Sun May 19 06:37:54 EDT 2019

STATUS

reviewed

approved

#21 by Joerg Arndt at Sun May 19 02:13:29 EDT 2019

STATUS

proposed

reviewed

#20 by Alois P. Heinz at Sat May 18 17:42:13 EDT 2019

STATUS

editing

proposed

Discussion

Sat May 18

17:54

Felix Fröhlich: "It was accepted in an earlier edit" does not seem like a reason to me to keep an incorrect and/or incomplete formula. Without specifying what k and m are, the formula didn't really make sense, anyway, right? And if a(n) = A064629(k) = A000040(m) is a valid way of expressing the intersection of these two sequences (I don't think it is), it is not really understandable. And one other editor agreed to deleting it, so I do not think I simply indiscriminately deleted something here.

17:55

Felix Fröhlich: Whith that being said, let's leave it at that.

#19 by Alois P. Heinz at Sat May 18 17:41:25 EDT 2019

DATA

7, 13, 119923, 146050183, 4039362385345521139, 289247481259011497824466400997481269, 1765256712749403700417549596608786383, 395766070055468241613007225643003404495980782673, 2596786183076854435238229837938226284218037897451862682304077097493117

#18 by Alois P. Heinz at Sat May 18 17:39:47 EDT 2019

MAPLE

select(isprime, [4&^n mod 3^n$n=1..200])[]; # Alois P. Heinz, May 18 2019

CROSSREFS

Cf. A000040, A000079, A000244, A064629, A178985.

#17 by Alois P. Heinz at Sat May 18 17:35:58 EDT 2019

FORMULA

a(n) = A064629(k) = A000040(m).

{ A000040 } intersect { A064629 }.

#16 by Alois P. Heinz at Sat May 18 17:34:33 EDT 2019

FORMULA

a(n) = A064629(k) = A000040(m).

STATUS

reviewed

editing

#15 by Sean A. Irvine at Sat May 18 17:29:12 EDT 2019

STATUS

proposed

reviewed

Discussion

Sat May 18

17:34

Alois P. Heinz: Please: do not delete everything that you do not understand.  It was accepted in an earlier edit.  You should try to understand the intention of the formula.

#14 by Felix Fröhlich at Sat May 18 17:24:19 EDT 2019

STATUS

editing

proposed

Discussion

Sat May 18

17:29

Sean A. Irvine: Agreed, formula was not useful.

#13 by Felix Fröhlich at Sat May 18 17:23:36 EDT 2019

PROG

(PARI) terms(n) = my(i=0); for(k=0, oo, if(i>=n, break); my(x=lift(Mod(4, 3^k)^k)); if(ispseudoprime(x), print1(x, ", "); i++))

/* Print initial 7 terms as follows: */

terms(7) \\ Felix Fröhlich, May 18 2019