%I A109839
%S A109839 1,10,11,20,21,16400,16401,16410,16411,16420,16421,16300,16301,16310,
%T A109839 16311,16320,16321,16200,16201,16210,16211,16220,16221,16100,16101,
%U A109839 16110,16111,16120,16121,16000,16001,16010,16011,16020,16021,15400
%N A109839 Negative numbers written in a bits-of-Pi/primorial base system.
%C A109839 A109838 describes this representation system which is my example of a 
               type appearing in one of Long's exercises.
%D A109839 Calvin T. Long, Elementary Introduction to Number Theory, 2nd ed., D.C. 
               Heath and Company, 1972, p. 30.
%e A109839 a(6) = 16400 because -6 = -210 + 180 + 24 = ((-1)^1)*1*210 + ((-1)^0)*6*30 
               + ((-1)^0)*4*6 + ((-1)^1)*0*2 + ((-1)^1)*0*1, where 1,1,0,0,1 are 
               the first five terms of A004601 and 1,2,6,30,210 are the first five 
               terms of A002110.
%Y A109839 Cf. A109838 (nonnegative integers represented similarly), A004601 (Pi 
               in binary), A002110 (primorials), A049345 (primorial base).
%Y A109839 Sequence in context: A049345 A007623 A109827 this_sequence A087486 A102626 
               A014418
%Y A109839 Adjacent sequences: A109836 A109837 A109838 this_sequence A109840 A109841 
               A109842
%K A109839 base,nonn
%O A109839 1,2
%A A109839 Rick L. Shepherd (rshepherd2(AT)hotmail.com), Jul 05 2005