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%I #10 Feb 03 2015 12:01:56
%S 3,4,5,5,5,6,7,7,7,8,9,9,9,10,10,10,10,10,11,12,12,12,12,12,13,13,13,
%T 14,15,15,15,16,16,16,16,16,17,17,17,17,17,18,19,19,19,19,19,20,20,20,
%U 21,22,22,22,22,22,23,23,23,24,24,24,24,24,25,25,25,25,25,25,25,26,26
%N a(n)=A002808(n)-n, difference between n-th composite and n.
%C a(n) = the number of numbers of set {1, prime} (A008578(n)) less than n-th composite numbers (A002808(n)). a(n) = inverse (frequency distribution) sequence of A162177(n), i.e. number of terms of sequence A162177(n) less than n for n >= 1. a(n) = A002808(n) + A162177(n) - A158611(n+1) for n >= 1. a(n) = A002808(n) + A162177(n) - A008578(n) for n >= 1. [From _Jaroslav Krizek_, Jul 23 2009]
%H Harvey P. Dale, <a href="/A073169/b073169.txt">Table of n, a(n) for n = 1..1000</a>
%F a(n)=1+A073425(n). [From _R. J. Mathar_, Jul 31 2009]
%t c[n_Integer] := FixedPoint[n+PrimePi[ # ]+1&, n] Table[c[w]-w, {w, 1, 128}]
%t With[{c=Select[Range[100],CompositeQ]},#[[1]]-#[[2]]&/@Thread[ {c,Range[ Length[ c]]}]] (* _Harvey P. Dale_, Feb 03 2015 *)
%Y Cf. A007821, A022449, A000040, A002808, A073168.
%K nonn
%O 1,1
%A _Labos Elemer_, Jul 19 2002
%E Correction for change of offset in A158611 and A008578 in Aug 2009 _Jaroslav Krizek_, Jan 27 2010
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