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Search: id:A136802
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| A136802 |
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The composite with the largest prime factor in the n-th prime gap larger than 2. |
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+0
2
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| 10, 14, 22, 26, 34, 38, 46, 51, 58, 62, 69, 74, 82, 86, 94, 99, 106, 111, 122, 129, 134, 146, 155, 158, 166, 172, 178, 183, 194, 206, 218, 226, 232, 237, 249, 254, 262, 267, 274, 278, 291, 302, 309, 314, 326, 334, 346, 351, 358, 362, 371, 376, 382, 386, 394
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Pick the number in the interval [A136798(n),A136799(n)] with the largest prime factor.
The sequence is obtained from A114331 by removing terms in prime gaps of size 2.
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FORMULA
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A006530(a(n)) = A136801(n).
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EXAMPLE
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a(1)=10 because at N=10 the largest prime factor is 5.
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MAPLE
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A006530 := proc(n) max( op(numtheory[factorset](n))) ; end:
A136798 := proc(n) local a; if n = 1 then 8; else a := nextprime( procname(n-1))+1 ; while nextprime(a)-a <=2 do a := nextprime(a)+1 ; od; RETURN(a) ; fi; end:
A136802 := proc(n) local c, lpf, a; c := A136798(n) ; lpf := A006530(c) ; a := c; while not isprime(c+1) do c := c+1 ; if A006530(c) > lpf then a := c ; lpf := A006530(c) ; fi; od: a ; end:
seq(A136802(n), n=1..80) ; # R. J. Mathar, May 27 2009
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CROSSREFS
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Cf. A136798, A136799, A136800, A136801.
Sequence in context: A138511 A167611 A151740 this_sequence A084278 A069207 A136197
Adjacent sequences: A136799 A136800 A136801 this_sequence A136803 A136804 A136805
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KEYWORD
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easy,nonn
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AUTHOR
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Enoch Haga (Enokh(AT)comcast.net), Jan 24 2008
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EXTENSIONS
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Edited by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 27 2009
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