%I A057636
%S A057636 19,139,3089,18839,123229,2134519,12130109,23884639,363289219,
%T A057636 9568590299,24037796539,130426565719,405033487139,3553144754209,
%U A057636 4010803176619
%N A057636 Initial prime in first sequence of n primes congruent to 4 modulo 5. 
               The first prime in a sequence of length n all ending with the digit 
               9.
%H A057636 J. K. Andersen, <a href="http://users.cybercity.dk/~dsl522332/math/congruent-primes.htm">
               Consecutive Congruent Primes</a>.
%e A057636 a(5) = 123229 because this number is the first in a sequence of 5 consecutive 
               primes all of the form 5n + 4.
%t A057636 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 ] != {4}, k = NextPrime[ 
               k ]; a = Take[ AppendTo[ a, Mod[ k, 5 ] ], -n ] ]; p = NestList[ 
               PrevPrime, k, n ]; Print[ p[ [ -2 ] ] ]; p = p[ [ -1 ] ], {n, 1, 
               9} ]
%Y A057636 Cf. A054681, A057618, A057631, A068150.
%Y A057636 Sequence in context: A142746 A139902 A140624 this_sequence A104046 A060104 
               A110694
%Y A057636 Adjacent sequences: A057633 A057634 A057635 this_sequence A057637 A057638 
               A057639
%K A057636 nonn
%O A057636 1,1
%A A057636 Robert G. Wilson v (rgwv(AT)rgwv.com), Oct 10 2000
%E A057636 Phil Carmody gives a(15)= 4010803176619 in A054681
%E A057636 More terms from Jens Kruse Andersen (jens.k.a(AT)get2net.dk), Jun 03 
               2006