|
%I #10 Oct 10 2019 11:53:06
%S 1,1,2,5,11,5,2,3,7,17,23,10,2,51,41,7,35,23,2,9,55,45,48,13,12,53,22,
%T 30,2,161,2,5,80,86,102,199,2,11,94,31,83,257,2,137,46,281,2,111,16,
%U 36,41,171,107,125,14,48,7,13,2,163,2,467,181,121,179,266,2,137,167,323,2
%N a(1)=1. a(n) = the numerator of the sum of the reciprocals of the earlier terms of the sequence which divide n.
%e The sequence's terms, among terms a(1) through a(9), which divide 10 are a(1)=1, a(2)=1, a(3)=2, a(4)=5, a(6)=5 and a(7)=2. So a(10) is the numerator of 1 +1 +1/2 +1/5 +1/5 +1/2 = 17/5, which is 17.
%t f[l_List] := Sum[1/l[[k]], {k, Length[l]}];g[l_List] := Block[{n = Length[l] + 1},Append[l, Numerator@f[Select[l, Mod[n, # ] == 0 &]]]];Nest[g, {1}, 70] (* _Ray Chandler_, Jan 04 2007 *)
%Y Cf. A127012.
%K nonn
%O 1,3
%A _Leroy Quet_, Jan 02 2007
%E Extended by _Ray Chandler_, Jan 04 2007
|
