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A138980
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a(0)=1; for n>=1, a(n) = smallest prime > a(n-1) such that (sum{k=0 to n} a(k)) is composite.
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3
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1, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281
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OFFSET
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0,2
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COMMENTS
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Although superficially similar to A049561, the two sequences are in fact quite different (see for example A138982).
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LINKS
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MAPLE
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A138980 := proc(n) option remember ; local i, p ; if n = 0 then 1 ; else for p from nextprime(A138980(n-1)) do if isprime(p) then if not isprime( p+add(A138980(i), i=0..n-1) ) then RETURN(p) ; fi ; fi ; od: fi ; end: seq(A138980(n), n=0..120) ; # R. J. Mathar Apr 30 2008
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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