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A113478
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Number of cuban primes less than 10^n.
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2
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0, 1, 4, 11, 28, 64, 173, 438, 1200, 3325, 9289, 26494, 76483, 221530, 645685, 1895983, 5593440, 16578830, 49347768
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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LINKS
| Eric Weisstein's World of Mathematics, Cuban Prime
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EXAMPLE
| 7, 19, 37, 61, 127 are the first few cuban primes, so a(1)=1 and a(2)=4
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PROG
| (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
| Cf. A002407, A002504.
Sequence in context: A176759 A096124 A090539 * A056601 A003230 A099326
Adjacent sequences: A113475 A113476 A113477 * A113479 A113480 A113481
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KEYWORD
| nonn,more
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AUTHOR
| Eric Weisstein (eric(AT)weisstein.com), Jan 10, 2006
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EXTENSIONS
| a(15)-a(18) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Feb 05 2010
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