|
%I #9 Jun 13 2014 19:21:46
%S 2,5483,25373,182243,5379113,5379113,1734847733,12196390601,
%T 17619405959,213529133423,2732797330031
%N Initial prime in first sequence of n primes congruent to 2 modulo 9.
%H J. K. Andersen, <a href="http://primerecords.dk/congruent-primes.htm">Consecutive Congruent Primes</a>.
%e a(2) = 5483 because this number is the first in a sequence of 2 consecutive primes all of the form 9n + 2.
%t NextPrime[ n_Integer ] := Module[ {k = n + 1}, While[ ! PrimeQ[ k ], k++ ]; Return[ k ] ]; PrevPrime[ n_Integer ] := Module[ {k = n - 1}, While[ ! PrimeQ[ k ], k-- ]; Return[ k ] ]; p = 0; Do[ a = Table[ -1, {n} ]; k = Max[ 1, p ]; While[ Union[ a ] != {2}, k = NextPrime[ k ]; a = Take[ AppendTo[ a, Mod[ k, 9 ] ], -n ] ]; p = NestList[ PrevPrime, k, n ]; Print[ p[ [ -2 ] ] ]; p = p[ [ -1 ] ], {n, 1, 6} ] a(7) > 331804250.
%K nonn
%O 1,1
%A _Robert G. Wilson v_, Oct 11 2000
%E More terms from _Jens Kruse Andersen_, May 31 2006
|
