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A095218
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(Product of composite numbers among next n numbers) - (product of primes among next n numbers).
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0
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0, -5, 19, 713, 2377, 120637, 259459177, 1357170301, 4929659569, 42608389821509, 11912739135894001, 59907396092196739, 20458385028296632427, 7926428532945161230909, 4693751193479184763610081, 328774885640356760904499183363
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OFFSET
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1,2
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COMMENTS
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Let c = product of composite numbers in the range [n(n-1)/2 + 1, n(n+1)/2], let p = product of prime numbers in the same range; then a(n) = c - p. Empty products = 1 by convention.
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LINKS
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EXAMPLE
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n = 1: no primes or composites hence 1-1= a(1)=0; n=2: range = 2 and 3, a(2)= (Product of composite numbers among next n numbers) - (product of primes among next n numbers) = empty product of composite numbers - 6 = 1-6 = -5; a(3)= 4*6 -5 as the next 3 numbers are (4,5,6).
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CROSSREFS
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KEYWORD
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sign,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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