A104094 - OEIS

%I #16 Apr 21 2024 16:08:20

%S 7,79,727,6553,59029,531383,4782961,43046623,387420479,3486784393,

%T 31381059607,282429536453,2541865828309,22876792454939,

%U 205891132094623,1853020188851807,16677181699666513,150094635296999111

%N Largest prime <= 9^n.

%H Robert Israel, <a href="/A104094/b104094.txt">Table of n, a(n) for n = 1..1046</a>

%F a(n) = 9^n - A013604(2*n) = A001019(n) - A013604(2*n), n > 0. _A.H.M. Smeets_, Aug 12 2019

%p f:= n -> prevprime(9^n):

%p map(f, [$1..30]); # _Robert Israel_, Aug 12 2019

%t NextPrime[#,-1]&/@(9^Range[20]) (* _Harvey P. Dale_, Apr 21 2024 *)

%o (PARI) g(n,b) = for(x=0,n,print1(precprime(b^x)","))

%Y Cf. A013604.

%Y Largest prime <= b^n: 2^n-A013603(n), 3^n-A013604(n), 4^n-A013606(n), 5^n-A013605(n), 6^n-A013607(n), 7^n-A013608(n), 8^n-A013603(3*n), 10^n-A033874(n).

%K easy,nonn

%O 1,1

%A _Cino Hilliard_, Mar 03 2005