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A102343
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Numbers k such that k*10^3 + 777 is prime.
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1
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1, 2, 11, 19, 22, 26, 41, 43, 44, 47, 50, 53, 65, 67, 68, 71, 76, 79, 80, 83, 94, 97, 107, 110, 113, 115, 122, 124, 125, 131, 134, 136, 137, 145, 146, 152, 155, 158, 167, 169, 170, 173, 176, 181, 184, 199, 202, 211, 212, 226, 229, 232, 233, 250, 253, 254, 268, 272, 274, 281, 284, 286, 292, 295, 298, 299
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OFFSET
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1,2
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COMMENTS
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From Ulrich Krug (leuchtfeuer37(AT)gmx.de), Apr 27 2009: (Start)
The sequence is infinite by Dirichlet's theorem about primes in arithmetic progression.
No term of the sequence is of form 3k, because the sum of digits of 10^3*3k + 333 = 3*(10^3 + 259) is divisible by 3, violating the requirement of the definition. (End)
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LINKS
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EXAMPLE
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k=1: 1*10^3 + 777 = 1777 is prime, hence 1 is in the sequence.
k=50: 50*10^3 + 777 = 50777 is prime, hence 50 is in the sequence.
k=97: 97*10^3 + 777 = 97777 is prime, hence 97 is in the sequence.
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MATHEMATICA
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Select[Range[300], PrimeQ[1000#+777]&] (* Harvey P. Dale, Jun 06 2022 *)
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PROG
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(Magma) [ n: n in [0..300] | IsPrime(n*10^3+777) ];
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CROSSREFS
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KEYWORD
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nonn,base,easy
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AUTHOR
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EXTENSIONS
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Extended by Ulrich Krug (leuchtfeuer37(AT)gmx.de), Apr 27 2009
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STATUS
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approved
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