A178998 Primes of the form 4^k mod 3^k.

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

Offset

1,1

Links

Table of n, a(n) for n=1..9.

Formula

{ A000040 } intersect { A064629 }.

Maple

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

Mathematica

Select[Table[PowerMod[4, n, 3^n], {n, 100}], PrimeQ] (* Alonso del Arte, Jan 03 2011 *)

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

Crossrefs

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

Sequence in context: A201181 A130594 A227173 * A188929 A258767 A169845

Adjacent sequences: A178995 A178996 A178997 * A178999 A179000 A179001

Keyword

nonn

Author

Juri-Stepan Gerasimov, Jan 03 2011

Status

approved