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A201786
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Primes of the form 5*k^2 - 4.
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1
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41, 241, 401, 601, 1801, 3121, 4201, 4801, 5441, 6121, 6841, 9241, 13001, 15121, 17401, 19841, 21121, 22441, 23801, 26641, 29641, 32801, 45121, 47041, 51001, 57241, 63841, 75641, 78121, 91121, 96601, 99401, 102241, 108041, 114001, 117041
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OFFSET
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1,1
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COMMENTS
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Also, primes of the form 20*k^2 + 20*k + 1. - Jan Rider, May 22 2018
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LINKS
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MATHEMATICA
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Select[Table[5n^2-4, {n, 1, 1000}], PrimeQ]
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PROG
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(Magma) [a: n in [1..400] | IsPrime(a) where a is 5*n^2-4];
(PARI) lista(nn) = for (n=1, nn, if (isprime(p=5*n^2-4), print1(p, ", ")); ); \\ Michel Marcus, May 22 2018
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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