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Search: id:A139084
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| A139084 |
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a(n) = (smallest prime-power among the largest powers dividing n of each prime dividing n) * (smallest prime-power among the largest powers dividing (n+1) of each prime dividing (n+1)). |
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3
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| 2, 6, 12, 20, 10, 14, 56, 72, 18, 22, 33, 39, 26, 6, 48, 272, 34, 38, 76, 12, 6, 46, 69, 75, 50, 54, 108, 116, 58, 62, 992, 96, 6, 10, 20, 148, 74, 6, 15, 205, 82, 86, 172, 20, 10, 94, 141, 147, 98, 6, 12, 212, 106, 10, 35, 21, 6, 118, 177, 183, 122, 14, 448, 320, 10, 134
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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The largest powers dividing 44 of each prime dividing 44 are 2^2 and 11^1. The least of these is 2^2 =4. The largest powers dividing 45 of each prime dividing 45 are 3^2 and 5^1. The least of these is 5^1 = 5. So a(44) = 4 * 5 = 20.
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LINKS
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Leroy Quet, Home Page (listed in lieu of email address)
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FORMULA
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a(n) = A034684(n) * A034684(n+1). [From Franklin T. Adams-Watters (FrankTAW(AT)Netscape.net), Apr 09 2009]
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PROGRAM
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Contribution from Franklin T. Adams-Watters (FrankTAW(AT)Netscape.net), Apr 09 2009: (Start)
(PARI) minpp(n)=local(m, r, pp); if(n==1, 1, m=factor(n); r=m[1, 1]^m[1, 2]; for(i=2, matsize(m)[1], pp=m[i, 1]^m[i, 2]; if(pp<r, r=pp)); r)
vector(80, i, minpp(i)*minpp(i+1)) (End)
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CROSSREFS
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Cf. A139082, A139083.
Sequence in context: A053660 A104969 A065005 this_sequence A086958 A130492 A152222
Adjacent sequences: A139081 A139082 A139083 this_sequence A139085 A139086 A139087
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KEYWORD
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nonn
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AUTHOR
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Leroy Quet Apr 07 2008
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EXTENSIONS
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More terms from Franklin T. Adams-Watters (FrankTAW(AT)Netscape.net), Apr 09 2009
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