

A057621


Initial prime in first sequence of n primes congruent to 2 modulo 3.


1



2, 23, 47, 251, 1889, 7793, 43451, 243161, 726893, 759821, 1820111, 1820111, 10141499, 19725473, 19725473, 136209239, 400414121, 400414121, 489144599, 489144599, 766319189, 766319189, 21549657539, 21549657539, 21549657539
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


COMMENTS

Same as A057622 except for a(1).  Jens Kruse Andersen, May 30 2006


LINKS

Giovanni Resta, Table of n, a(n) for n = 1..35 (terms < 4*10^14)
J. K. Andersen, Consecutive Congruent Primes.


EXAMPLE

a(12) = 1820111 because this number is the first in a sequence of 12 consecutive primes all of the form 3n + 2.


MATHEMATICA

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, 3 ] ], n ] ]; p = NestList[ PrevPrime, k, n ]; Print[ p[ [ 2 ] ] ]; p = p[ [ 1 ] ], {n, 1, 18} ] a(19) > 434562473.


CROSSREFS

Sequence in context: A105440 A139831 A049592 * A074809 A084237 A106928
Adjacent sequences: A057618 A057619 A057620 * A057622 A057623 A057624


KEYWORD

nonn


AUTHOR

Robert G. Wilson v, Oct 09 2000


EXTENSIONS

More terms from Jens Kruse Andersen, May 30 2006


STATUS

approved



