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 A090076 a(n) = prime(n)*prime(n+2). 6
 10, 21, 55, 91, 187, 247, 391, 551, 713, 1073, 1271, 1591, 1927, 2279, 2773, 3233, 3953, 4331, 4891, 5609, 6059, 7031, 8051, 8989, 9991, 10807, 11227, 12091, 13843, 14803, 17399, 18209, 20413, 20989, 23393, 24613, 26219, 28199, 29893, 31313 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Subsequence of A192133. [Reinhard Zumkeller, Jun 26 2011] LINKS EXAMPLE a(5) = prime(5)*prime(7) = 11*17 = 187. MATHEMATICA Table[Prime[n] Prime[n + 2], {n, 1, 40}] (* from Robert G. Wilson v Jan 22 2004 *) Last[#]First[#]&/@Partition[Prime[Range[50]], 3, 1] (* Harvey P. Dale, May 08 2013 *) PROG (Mupad) ithprime(i)*ithprime(i+2) \$ i = 1..40 // Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Feb 26 2007 (Sage) def prime_gaps(n):     primegaps = []     nprimes = primes_first_n(n+1)     for i in range(2, n+1):         primegaps.append(nprimes[i]*nprimes[i-2])     return primegaps print prime_gaps(60) # Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jul 08 2008 CROSSREFS Subset of the squarefree semiprimes, A006881. Cf. A006094, A090090. Sequence in context: A042309 A215757 A048697 * A156592 A045973 A095679 Adjacent sequences:  A090073 A090074 A090075 * A090077 A090078 A090079 KEYWORD easy,nonn,changed AUTHOR Felix Tubiana (fat2(AT)columbia.edu), Jan 21 2004 EXTENSIONS Extended by Robert G. Wilson v, Jan 22 2004 STATUS approved

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