
OFFSET

1,1


COMMENTS

See comments for A057472. Examined in base 12, all n must be even and all primes must be 1primes. For example, 241 is 181 in base 12.
The n<1000 that yield primes are 2, 8, 248.  T. D. Noe, Nov 16 2006


LINKS

Table of n, a(n) for n=1..2.


FORMULA

a(n) = nth number such that 2*11^k1 that is prime for some k.
a(n) = 2*11^A120378(n)1. [From R. J. Mathar, Mar 06 2010]


EXAMPLE

a(1)=241 since 2*11^21=241 is the first prime.


MAPLE

for w to 1 do for k from 1 to 2000 do n:=2*11^k1; if isprime(n) then printf("%d, %d", k, n) fi od od;


MATHEMATICA

Select[2*11^Range[1000]1, PrimeQ]  T. D. Noe, Nov 16 2006


CROSSREFS

Cf. A000043, A000668, A002957, A002959, A003307, A079363, A055558.
Sequence in context: A207286 A217998 A183891 * A321821 A171242 A259092
Adjacent sequences: A120374 A120375 A120376 * A120378 A120379 A120380


KEYWORD

nonn,bref


AUTHOR

Walter Kehowski, Jun 28 2006


EXTENSIONS

Corrected by T. D. Noe, Nov 16 2006


STATUS

approved

