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%I #14 Oct 30 2018 10:31:02
%S 4,6,9,11,18,21,24,27,30,32,34,42,44,51,53,58,62,66,68,72,77,80,82,84,
%T 87,91,94,97,99,101,106,114,121,125,127,132,135,137,139,141,143,146,
%U 150,154,157,162,166,168,170,172,175,177,180,186,189,191,193,197
%N Positions of local maxima in differences of primes, A001223.
%C Or, numbers n such that A001223(n-1) < A001223(n) > A001223(n+1).
%C Corresponding values of local maxima (4, 4, 6, 6, 6, 6, 8,...) are in A198697.
%t nn = 1001; t = Differences[Prime[Range[nn]]]; t2 = {}; Do[If[t[[n - 1]] < t[[n]] && t[[n]] > t[[n + 1]], AppendTo[t2, {n, t[[n]]}]], {n, 2, nn - 2}]; Transpose[t2][[1]] (* _T. D. Noe_, Dec 27 2011 *)
%Y Cf. A196175 local minima in A001223 (first differences of primes), A198697.
%K nonn
%O 1,1
%A _Zak Seidov_, Oct 29 2011