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Search: id:A113478
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| A113478 |
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Number of cuban primes less than 10^n. |
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+0
2
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| 0, 1, 4, 11, 28, 64, 173, 438, 1200, 3325, 9289, 26494, 76483, 221530, 645685
(list; graph; listen)
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OFFSET
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0,3
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LINKS
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Eric Weisstein's World of Mathematics, Cuban Prime
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EXAMPLE
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7, 19, 37, 61, 127 are the first few cuban primes, so a(1)=1 and a(2)=4
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PROGRAM
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(PARI) A113478(n)=sum(k=1, sqrt(10^n/3), isprime(3*k*(k+1)+1)) - M. F. Hasler (Maximilian.Hasler(AT)gmail.com), Nov 28 2007
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CROSSREFS
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Cf. A002407, A002504.
Sequence in context: A014151 A096124 A090539 this_sequence A056601 A003230 A099326
Adjacent sequences: A113475 A113476 A113477 this_sequence A113479 A113480 A113481
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KEYWORD
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nonn,more
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AUTHOR
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Eric Weisstein (eric(AT)weisstein.com), Jan 10, 2006
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