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A168141 a(n) = PrimePi(n+1) - PrimePi(n-2). 1

%I

%S 1,2,2,2,1,2,1,1,0,1,1,2,1,1,0,1,1,2,1,1,0,1,1,1,0,0,0,1,1,2,1,1,0,0,

%T 0,1,1,1,0,1,1,2,1,1,0,1,1,1,0,0,0,1,1,1,0,0,0,1,1,2,1,1,0,0,0,1,1,1,

%U 0,1,1,2,1,1,0,0,0,1,1,1,0,1,1,1,0,0,0,1,1,1,0,0,0,0,0,1,1,1,0,1,1,2,1,1,0

%N a(n) = PrimePi(n+1) - PrimePi(n-2).

%p A168141 := proc(n) numtheory[pi](n+1)-numtheory[pi](n-2) ; end proc: seq(A168141(n),n=1..120) ; # _R. J. Mathar_, Nov 19 2009

%Y Cf. A000720, A090406.

%K nonn

%O 1,2

%A _Juri-Stepan Gerasimov_, Nov 19 2009

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Last modified January 17 23:37 EST 2020. Contains 330995 sequences. (Running on oeis4.)