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a(n) = floor((4/3)*(2+prime(n)) - prime(n+1)).
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%I #10 Apr 13 2016 08:59:03

%S 2,1,2,1,4,3,6,5,4,10,7,11,14,13,12,14,20,17,21,24,21,25,24,24,31,34,

%T 33,36,35,26,41,40,46,39,50,47,49,53,52,54,60,53,64,63,66,57,61,73,76,

%U 75,74,80,73,80,82,84,90,87,91,94,87,86,101,104,103,94,107

%N a(n) = floor((4/3)*(2+prime(n)) - prime(n+1)).

%C Conjecture: a(n)>0 for all n (cf. A062234, A207480).

%H Vincenzo Librandi, <a href="/A208548/b208548.txt">Table of n, a(n) for n = 1..1000</a>

%t Table[Floor[(4/3)*(2+Prime[n])-Prime[n+1]],{n,100}]

%t Floor[4/3*(2+#[[1]])-#[[2]]]&/@Partition[Prime[Range[70]],2,1] (* _Harvey P. Dale_, Apr 13 2016 *)

%Y Cf. A062234, A207480.

%K nonn

%O 1,1

%A _Zak Seidov_, Feb 28 2012