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A140390
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Nonprimes of the form 21k+1.
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1
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1, 22, 64, 85, 106, 148, 169, 190, 232, 253, 274, 295, 316, 358, 400, 442, 484, 505, 526, 568, 589, 610, 652, 694, 715, 736, 778, 799, 820, 841, 862, 904, 925, 946, 988, 1030, 1072, 1114, 1135, 1156, 1177, 1198, 1219, 1240, 1261, 1282, 1324
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OFFSET
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1,2
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COMMENTS
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The prime numbers 421=20*21+1 and 673=32*21+1, for example, are neither in here nor in A136069.
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LINKS
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MATHEMATICA
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PROG
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(Magma) [a: n in [0..90] | not IsPrime(a) where a is 21*n+1]; (* Vincenzo Librandi, Mar 22 2014 *)
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CROSSREFS
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KEYWORD
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nonn,less
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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