

A088622


Smallest prime obtained as the concatenation of a power of n followed by a 1, or 0 if no such number exists.


5



11, 41, 31, 41, 251, 61, 71, 641, 811, 101, 259374246011, 0, 131, 75295361, 151, 40961
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


COMMENTS

a(12) = 0. Subsidiary sequence: n such that 10*n^k +1 is composite for all k >0 (indices of zero entries in this sequence): see A088783.
a(17) is too large to display here. After a(17) the sequence continues: 181, 191, 4001, 211, 1368800680154120519681, 0, 241, 251, 6761, 271, 281, 7072811, 9001, 311, 0, 331, 0, 12251, 466561, 13691, 20851361, 23134411, 401


LINKS

Table of n, a(n) for n=1..16.


MATHEMATICA

f[n_] := Block[{k = 1}, While[ !PrimeQ[10*n^k + 1] && k != 1500, k++ ]; If[k == 1500, 0, 10*n^k + 1]]; Table[ f[n], {n, 1, 50}] (* Robert G. Wilson v, Oct 25 2003 *)


CROSSREFS

Cf. A088623, A088782, A088783.
Sequence in context: A073626 A065144 A089348 * A121171 A239790 A065079
Adjacent sequences: A088619 A088620 A088621 * A088623 A088624 A088625


KEYWORD

base,nonn


AUTHOR

Amarnath Murthy, Oct 19 2003


EXTENSIONS

Next term is too large to include.  Ray Chandler, Oct 23 2003
Extended by Robert G. Wilson v, Oct 25 2003


STATUS

approved



