

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
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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



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



KEYWORD

base,nonn


AUTHOR



EXTENSIONS

Next term is too large to include.  Ray Chandler, Oct 23 2003


STATUS

approved



