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Search: id:A136801
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| A136801 |
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Largest prime factor of the composites in the n-th prime gap larger than 2. |
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+0
6
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| 5, 7, 11, 13, 17, 19, 23, 17, 29, 31, 23, 37, 41, 43, 47, 11, 53, 37, 61, 43, 67, 73, 31, 79, 83, 43, 89, 61, 97, 103, 109, 113, 29, 79, 83, 127, 131, 89, 137, 139, 97, 151, 103, 157, 163, 167, 173, 13, 179, 181, 53, 47, 191, 193, 197, 199, 101, 139, 211, 109, 17, 223
(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 prime factor of numbers in the interval [A136798(n),A136799(n)].
The sequence is obtained from A052248 by removing terms from composites in prime gaps of size 2.
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EXAMPLE
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a(1)=5 because the composites in the run from 8, 9, 10 contain prime factors 2, 3, and 5, with 5 being the largest at N=10.
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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:
A136801 := proc(n) local a, i; i := A136798(n) ; a := A006530( i) ; while not isprime(i+1) do i := i+1 ; a := max(a, A006530(i)) ; od: a ; end:
seq(A136801(n), n=1..20) ; # R. J. Mathar, May 27 2009
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CROSSREFS
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Cf. A136798, A136799, A136800, A136802.
Sequence in context: A113909 A111906 A101550 this_sequence A106571 A067291 A007310
Adjacent sequences: A136798 A136799 A136800 this_sequence A136802 A136803 A136804
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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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