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A075076 Integers pertaining to A075075: a(n) = b(n-1)*b(n+1)/b(n) where b(n) is the n-th term of A075075.

%I A075076 #16 Jun 10 2015 10:16:13
%S A075076 2,3,2,10,6,4,15,6,20,12,12,30,12,28,6,33,14,7,44,13,14,34,26,15,51,
%T A075076 18,55,36,24,55,20,56,30,30,56,39,36,68,52,42,85,40,77,60,45,77,42,99,
%U A075076 56,56,99,72,80,54,57,30,46,38,29,23,62,58,37,31,82,74,38,123,38,86,114,39
%N A075076 Integers pertaining to A075075: a(n) = b(n-1)*b(n+1)/b(n) where b(n) is the n-th term of A075075.
%C A075076 This is not a permutation of the natural numbers since a(4)=a(2), a(9)=a(6), a(12)=a(11) etc. [From _Hagen von Eitzen_, May 16 2009]
%H A075076 Alois P. Heinz, <a href="/A075076/b075076.txt">Table of n, a(n) for n = 2..10000</a>
%p A075076 c:= proc() false end:
%p A075076 b:= proc(n) option remember; local k, m;
%p A075076        if n<3 then k:=n
%p A075076      else m:= denom(b(n-2) /b(n-1));
%p A075076           for k from m by m while c(k) do od
%p A075076        fi;
%p A075076        c(k):= true; k
%p A075076     end:
%p A075076 a:= n-> b(n-1)*b(n+1)/b(n):
%p A075076 seq(a(n), n=2..100);  # _Alois P. Heinz_, Jul 18 2012
%t A075076 Clear[b, c]; c[_] = False; b[n_] := b[n] = Module[{k, m}, If[n<3, k = n, m = Denominator[b[n-2]/b[n-1]]; For[k = m, c[k], k = k+m]]; c[k] = True; k];a[n_] := b[n-1]*b[n+1]/b[n]; Table[a[n], {n, 2, 100}] (* _Jean-François Alcover_, Jun 10 2015, after _Alois P. Heinz_ *)
%Y A075076 Cf. A075075.
%K A075076 nonn,look
%O A075076 2,1
%A A075076 _Amarnath Murthy_, Sep 09 2002
%E A075076 More terms from _Sascha Kurz_, Feb 03 2003