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Search: id:A076978
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| A076978 |
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Largest square-free number that divides the product of composite numbers between successive primes. |
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+0
1
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| 1, 2, 6, 30, 6, 210, 6, 2310, 2730, 30, 39270, 7410, 42, 7590, 46410, 1272810, 30, 930930, 82110, 6, 21111090, 1230, 48969690, 1738215570, 2310, 102, 144690, 6, 85470, 29594505363092670, 16770, 49990710, 138
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OFFSET
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1,2
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COMMENT
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a(35)=30, a(36)=300690390, a(37)=20223210, a(38)=1122990, a(39)=37916970, a(40)=351764490, a(41)=30, a(43)=6, a(44)=264810, a(45)=66; a(34) and a(42) are presently unknown. - Emeric Deutsch (deutsch(AT)duke.poly.edu), Jul 28 2006
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EXAMPLE
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a(5)=6 because 12 is the only composite number between the 5th and the 6th primes (11 and 13) and largest square-free divisor of 12 is 6.
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MAPLE
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with(numtheory): b:=proc(j) if issqrfree(j) then j else fi end: a:=proc(n) local B, BB: B:=divisors(product(i, i=ithprime(n)+1..ithprime(n+1)-1)): BB:=(seq(b(B[j]), j=1..nops(B))): max(BB); end: seq(a(n), n=1..33); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Jul 28 2006
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CROSSREFS
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Sequence in context: A124529 A088957 A030538 this_sequence A079615 A074168 A117213
Adjacent sequences: A076975 A076976 A076977 this_sequence A076979 A076980 A076981
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KEYWORD
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nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Oct 23 2002
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EXTENSIONS
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More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Jul 28 2006
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