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A102343 Numbers k such that k*10^3 + 777 is prime. 1
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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
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)
LINKS
EXAMPLE
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.
MATHEMATICA
Select[Range[300], PrimeQ[1000#+777]&] (* Harvey P. Dale, Jun 06 2022 *)
PROG
(Magma) [ n: n in [0..300] | IsPrime(n*10^3+777) ];
(PARI) is(n)=isprime(n*10^3+777) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
Cf. A157772, A102248, A159942. - Ulrich Krug (leuchtfeuer37(AT)gmx.de), Apr 27 2009
Sequence in context: A074926 A352932 A066144 * A023173 A018443 A163058
KEYWORD
nonn,base,easy
AUTHOR
Parthasarathy Nambi, Feb 20 2005
EXTENSIONS
Extended by Ulrich Krug (leuchtfeuer37(AT)gmx.de), Apr 27 2009
Edited by R. J. Mathar, Apr 30 2009
More terms from Vincenzo Librandi, May 01 2009
STATUS
approved

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Last modified March 19 06:32 EDT 2024. Contains 370953 sequences. (Running on oeis4.)