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%I #28 Mar 31 2017 22:48:29
%S 1,2,3,2,4,5,2,3,6,7,2,4,8,3,9,2,5,10,11,2,3,4,6,12,13,2,7,14,3,5,15,
%T 2,4,8,16,17,2,3,6,9,18,19,2,4,5,10,20,3,7,21,2,11,22,23,2,3,4,6,8,12,
%U 24,5,25,2,13,26,3,9,27,2,4,7,14,28,29,2,3,5,6,10,15,30,31,2,4,8,16,32,3,11,33,2,17,34,5,7,35
%N Take the list 1,2,3,4,... and replace each n with all d > 1 that divide n.
%C a(A002541(n)+1)=n; a(A002541(n)+2)=A020639(n+1). - _Reinhard Zumkeller_, Nov 22 2003
%C Seen as a triangle read by rows: T(1,1)=1 and T(n,k)=A027750(n,k+1) for n>1, 1<=k<A000005(n). - _Reinhard Zumkeller_, Oct 01 2012
%H Reinhard Zumkeller, <a href="/A027749/b027749.txt">Rows n = 1..250 of triangle, flattened</a>
%t Join[{1},Flatten[Rest[Divisors[#]]&/@Range[40]]] (* _Harvey P. Dale_, Jun 28 2011 *)
%o (Haskell)
%o a027749 n k = a027749_tabf !! (n-1) !! (k-1)
%o a027749_row n = a027749_tabf !! n
%o a027749_tabf = [1] : map tail (tail a027750_tabf)
%o -- _Reinhard Zumkeller_, Oct 01 2012, Oct 19 2011, Jul 11 2011
%Y Cf. A032741, A027750.
%K nonn,easy,nice,tabf
%O 1,2
%A _N. J. A. Sloane_
%E More terms from Scott Lindhurst (ScottL(AT)alumni.princeton.edu)
%E Keyword tabf added by _Reinhard Zumkeller_, Oct 01 2012
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