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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

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Last modified February 24 11:12 EST 2018. Contains 299603 sequences. (Running on oeis4.)