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A317743 Valleys in A064800: terms which are smaller than their neighbors. 1

%I

%S 14,18,20,27,30,32,35,38,42,44,51,54,57,59,62,67,68,72,74,80,87,90,93,

%T 98,102,104,110,114,123,128,131,132,135,138,140,143,147,150,152,158,

%U 163,164,171,174,179,182,187,192,194,198,200

%N Valleys in A064800: terms which are smaller than their neighbors.

%C From _Zak Seidov_, Sep 21 2018: (Start)

%C First second-order valley is a(514) = 516

%C with {521, 517, 516, 517, 520}.

%C First third-order valley is a(k=265827) = 265829

%C with {265833, 265831, 265830, 265829, 265831, 265832, 265834}.

%C Are there minima of higher order? (End)

%e a(1) = 14 is the first valley (local minimum) in A064800 as A064800(13) = 14 is less than A064800(12) = 15 and A064800(14) = 16.

%t Transpose[ Select[ Partition[(# + PrimeOmega[#]) & /@ Range[201], 3, 1], #[[1]] > #[[2]] < #[[3]] &]][[2]] (* _Giovanni Resta_, Aug 09 2018 *)

%o (PARI) lista(nn) = {my(v = vector(nn, n, n + bigomega(n))); for (n=2, nn, if ((v[n] < v[n-1]) && (v[n] < v[n+1]), print1(v[n], ", ")););} \\ _Michel Marcus_, Sep 07 2018

%Y Cf. A064800, A319504.

%K nonn

%O 1,1

%A _Zak Seidov_, Aug 05 2018

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Last modified August 17 23:13 EDT 2022. Contains 356204 sequences. (Running on oeis4.)