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 A130500 a(1)=1. a(n) = number of earlier terms of the sequence which divide (the number of positive integers which are <=n and missing from first (n-1) terms of sequence). 1

%I

%S 1,1,2,3,3,4,4,5,5,4,5,2,7,7,4,7,2,11,11,2,9,9,7,10,10,2,11,2,17,17,8,

%T 8,11,2,17,5,9,7,18,18,2,18,2,17,8,15,15,11,23,23,2,12,12,4,26,26,2,

%U 20,20,2,24,24,13,13,16,16,2,31,31,7,21,21,8,24,2,24,11,31,4,16,2,37,37,2,21

%N a(1)=1. a(n) = number of earlier terms of the sequence which divide (the number of positive integers which are <=n and missing from first (n-1) terms of sequence).

%e The positive integers which are <= 9 and are missing from the first 8 terms of the sequence are 6,7,8,9. The number of these integers is 4, so a(9) is the number of earlier terms which divide 4. Therefore a(9) = 5.

%Y Cf. A130501.

%K nonn

%O 1,3

%A _Leroy Quet_, May 31 2007

%E More terms from _Sean A. Irvine_, May 26 2010

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Last modified June 16 19:05 EDT 2021. Contains 345068 sequences. (Running on oeis4.)