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Search: id:A066490
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| A066490 |
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Number of primes of the form 4m+3 <= n. |
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+0
3
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| 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 11, 11, 12, 12, 12, 12, 13, 13, 13, 13, 13, 13, 13, 13, 13
(list; graph; listen)
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OFFSET
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1,7
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LINKS
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T. D. Noe, Table of n, a(n) for n=1..10000
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MATHEMATICA
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Table[ Length[ Select[ Union[ Table[ Prime[ PrimePi[i]], {i, 2, n}]], Mod[ #, 4] == 3 & ]], {n, 2, 100} ]
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PROGRAM
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(PARI) for(n=1, 100, print1(sum(i=1, n, if((i*isprime(i)-3)%4, 0, 1)), ", "))
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CROSSREFS
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Cf. A066339.
Sequence in context: A000523 A124156 A072749 this_sequence A124230 A090973 A076634
Adjacent sequences: A066487 A066488 A066489 this_sequence A066491 A066492 A066493
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KEYWORD
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easy,nonn
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 03 2002
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