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 A082931 a(1) = 1; a(n) = least k > a(n-1) such that a(i)+k is prime for some i < n and each prime of form a(i)+a(j) occurs for unique i <= j. 3

%I

%S 1,2,3,5,8,14,20,23,24,37,43,48,49,55,61,75,90,109,117,118,121,139,

%T 141,157,183,193,199,212,223,229,241,245,271,277,296,301,313,320,321,

%U 331,363,368,393,403,410,422,439,457,468,469,481,491,511,525,530,535,607

%N a(1) = 1; a(n) = least k > a(n-1) such that a(i)+k is prime for some i < n and each prime of form a(i)+a(j) occurs for unique i <= j.

%t a[1]=1; p[1]={2}; a[n_] := Module[{k, new}, For[k=a[n-1]+1, Intersection[p[n-1], (new=Select[(a/@Range[n-1])+k, PrimeQ])]!={}||new=={}, k++, Null]; p[n]=Union[p[n-1], new]; a[n]=k]

%Y Cf. A082932, A082933, A080435.

%K nonn

%O 1,2

%A _David W. Wilson_, Apr 14 2003

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Last modified September 27 03:08 EDT 2020. Contains 337380 sequences. (Running on oeis4.)