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%I #13 Aug 18 2015 00:34:38
%S 1,2,4,12,24,72,360,720,2160,8640,43200,302400,3931200,7862400,
%T 23587200,94348800,471744000,3302208000,29719872000,386358336000,
%U 9658958400000,19317916800000,57953750400000,231815001600000,1159075008000000,8113525056000000,73021725504000000
%N a(1)=1. a(n) = a(n-1)*(b(n-1)+1), where {b(k)} is the concatenated list of the positive divisors of the terms of {a(k)}.
%e The list of positive divisors of the terms of {a(k)} is (sequence A129644) 1;1,2;1,2,4;1,2,3,4,6,12;.... The n-th term of {a(k)} is product{k=1 to n-1}(A129644(k)+1).
%p A129643 := proc(nmax) local a,b,n,a_1; a := [1] ; b := [1] ; while nops(a) < nmax do n := nops(a)+1 ; a_1 := op(-1,a) ; a := [op(a),a_1*(op(n-1,b)+1)] ; a_1 := op(-1,a) ; if nops(b) < nmax then b := [op(b),op(numtheory[divisors](a_1))] ; fi ; od: RETURN(a) ; end: A129643(40) ; # _R. J. Mathar_, Oct 16 2007
%Y Cf. A129644.
%K nonn,base
%O 1,2
%A _Leroy Quet_, Apr 25 2007
%E More terms from _R. J. Mathar_, Oct 16 2007
%E Corrected by _N. J. A. Sloane_, Nov 04 2007
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