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A182089
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Numbers of the form (330*k+7)*(660*k+13)*(990*k+19)*(1980*k+37).
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1
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63973, 461574735553, 7103999557333, 35498632881313, 111463190499493, 271061745643873, 560604728986453, 1036648928639233, 1765997490154213, 2825699916523393, 4303052068178773, 6295596162992353, 8911120776276133, 12267660840782113, 16493497646702293
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OFFSET
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1,1
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COMMENTS
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Conjecture: C = (330k+7)*(660k+13)*(990k+19)*(1980k+37) is a Carmichael number if 330k+7, 660k+13, 990k+19 and 1980k+37 are all four prime numbers.
For 0<k<50 the condition is satisfied just for k = 0 and k = 1.
The next term is > 10^19.
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LINKS
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MATHEMATICA
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Table[(330 n + 7)*(660 n + 13)*(990 n + 19)*(1980 n + 37), {n, 0, 50}] (* G. C. Greubel, Aug 20 2017 *)
LinearRecurrence[{5, -10, 10, -5, 1}, {63973, 461574735553, 7103999557333, 35498632881313, 111463190499493}, 20] (* Vincenzo Librandi, Aug 21 2017 *)
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PROG
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(Magma) [(330*n+7)*(660*n+13)*(990*n+19)*(1980*n+37): n in [0..15]]; // Vincenzo Librandi, Aug 21 2017
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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