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A244270
Numbers n such that n1n2n3n4n5n6n7n8n9n is prime.
1
17, 53, 181, 313, 343, 377, 829, 859, 943, 1151, 1477, 1493, 1757, 1853, 1909, 2011, 2161, 2267, 2287, 2371, 2521, 2549, 2569, 2773, 2791, 2803, 2849, 2891, 3019, 3157, 3401, 3617, 3811, 3821, 3979, 4273, 4319, 4481, 4483, 4493, 4499, 4607, 5081, 5239, 5299, 5351, 5353, 5399, 5567, 5603, 5669, 5761
OFFSET
1,1
COMMENTS
a(n) is odd for all n.
EXAMPLE
17117217317417517617717817917 is prime. Thus, 17 is a member of this sequence.
PROG
(PARI) for(n=1, 10^4, b=""; for(i=2, 20, if(i==Mod(1, 2), b=concat(b, Str((i-1)/2))); if(i==Mod(0, 2), b=concat(b, Str(n)))); if(ispseudoprime(eval(b)), print1(n, ", ")))
CROSSREFS
Sequence in context: A033213 A082078 A107175 * A244271 A224269 A125637
KEYWORD
nonn,base,less
AUTHOR
Derek Orr, Jun 24 2014
STATUS
approved