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A088640
Smallest number suffixed to concatenation of n times n gives a prime.
1
2, 1, 3, 1, 9, 7, 29, 1, 3, 7, 39, 1, 23, 1, 97, 1, 91, 37, 59, 9, 93, 19, 97, 61, 293, 61, 3, 1, 57, 7, 43, 61, 7, 53, 31, 127, 353, 67, 841, 187, 9, 3, 179, 429, 127, 97, 3, 319, 11, 51, 39, 191, 33, 3, 41, 7, 39, 47, 73, 81, 401, 57, 441, 571, 957, 997, 1, 19, 291, 173, 9, 417
OFFSET
0,1
EXAMPLE
a(6) = 29 and 66666629 is prime.
MAPLE
a:= proc(n) local d, h, s;
s:= parse(cat(0, n$n));
for d from 0 do
for h to 10^d-1 do
if isprime(s+h) then return h fi
od:
s:= s*10;
od
end:
seq(a(n), n=0..75); # Alois P. Heinz, Feb 11 2021
CROSSREFS
Cf. A088639.
Sequence in context: A198315 A126761 A090559 * A186725 A301935 A237978
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy, Oct 27 2003
EXTENSIONS
More terms from Ray Chandler, Nov 01 2003
a(0)=2 prepended by Alois P. Heinz, Feb 11 2021
STATUS
approved