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A280084
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1 together with the Pythagorean primes.
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1
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1, 5, 13, 17, 29, 37, 41, 53, 61, 73, 89, 97, 101, 109, 113, 137, 149, 157, 173, 181, 193, 197, 229, 233, 241, 257, 269, 277, 281, 293, 313, 317, 337, 349, 353, 373, 389, 397, 401, 409, 421, 433, 449, 457, 461, 509, 521, 541, 557, 569, 577, 593, 601, 613, 617
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OFFSET
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1,2
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COMMENTS
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Positive noncomposite numbers of the form 4k + 1.
Positive noncomposite numbers in A020668.
Essentially the same as A002313 and A002144. - R. J. Mathar, Jan 04 2017
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LINKS
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Table of n, a(n) for n=1..55.
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FORMULA
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A002144 UNION {1}. - R. J. Mathar, Jan 04 2017
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PROG
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(MAGMA) [1] cat [a: n in [0..200] | IsPrime(a) where a is 4*n + 1 ];
(PARI) is(n)=if(isprime(n), n%4==1, n==1) \\ Charles R Greathouse IV, Oct 10 2018
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CROSSREFS
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Cf. A002144, A006005, A008578, A020668.
Sequence in context: A175768 A351535 A002144 * A319287 A192592 A349900
Adjacent sequences: A280081 A280082 A280083 * A280085 A280086 A280087
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KEYWORD
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nonn,easy,less
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AUTHOR
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Juri-Stepan Gerasimov, Dec 25 2016
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STATUS
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approved
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