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Search: id:A090090
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| A090090 |
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a(n) = prime(n)*prime(n+3). |
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+0
7
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| 14, 33, 65, 119, 209, 299, 493, 589, 851, 1189, 1333, 1739, 2173, 2537, 2867, 3551, 4189, 4453, 5293, 5893, 6497, 7663, 8383, 9167, 10379, 11009, 11639, 13589, 14279, 15481, 17653, 19519, 20687, 21823, 24287, 25217, 27161, 29177, 30227, 33043
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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a(5) = prime(5)*prime(8) = 11*19 = 209.
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MATHEMATICA
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Table[ Prime[n] Prime[n + 3], {n, 1, 40}] (from Robert G. Wilson v Jan 22 2004)
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PROGRAM
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def prime_gaps(n): primegaps = [] nprimes = primes_first_n(n+1) for i in range(3, n+1): primegaps.append(nprimes[i]*nprimes[i-3]) return primegaps print prime_gaps(60) - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jul 08 2008
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CROSSREFS
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Subset of the square-free semiprimes, A006881. Cf. A006094, A090076.
Sequence in context: A018959 A107484 A076329 this_sequence A116150 A019272 A018949
Adjacent sequences: A090087 A090088 A090089 this_sequence A090091 A090092 A090093
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KEYWORD
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easy,nonn
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AUTHOR
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Felix Tubiana (fat2(AT)columbia.edu), Jan 21 2004
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EXTENSIONS
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Extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 22 2004
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