cp's OEIS Frontend

A181868 a(1) = 10, a(2) = 1. For n >= 3, a(n) = concatenate a(n-1), a(n-2), ..., a(1) and then divide the resulting number by a(n-1).

%I A181868 #6 Mar 30 2012 18:40:13
%S A181868 10,1,110,1001,1000110,10000001001,100000000001000110,
%T A181868 10000000000000000010000001001,
%U A181868 10000000000000000000000000000100000000001000110,1000000000000000000000000000000000000000000000010000000000000000010000001001
%N A181868 a(1) = 10, a(2) = 1. For n >= 3, a(n) = concatenate a(n-1), a(n-2), ..., a(1) and then divide the resulting number by a(n-1).
%C A181868 Compare with A181756.
%C A181868 The calculations for the first few values of the sequence are
%C A181868 ... a(3) = 110/1 = 110
%C A181868 ... a(4) = 110110/110 = 1001
%C A181868 ... a(5) = 1001110110 /1001 = 1000110
%C A181868 ... a(6) = 10001101001110110/1000110 = 10000001001.
%C A181868 The above calculations are in base 10, but we get exactly the same results when working in an arbitrary base b with initial values a(1) = 10 (= b in base b), a(2) = 1.
%C A181868 For similarly defined sequences see A181754 through A181756 and A181864 through A181870.
%F A181868 a(n+2) = a(n) + 10^(A000032(n+1)-1), n>=1.
%F A181868 a(n) has A000032(n-1) digits.
%p A181868 #A181868
%p A181868 M:=10:
%p A181868 a:=array(1..M):s:=array(1..M):
%p A181868 a[1]:=10:a[2]:=1:
%p A181868 s[1]:=convert(a[1],string):
%p A181868 s[2]:=cat(convert(a[2],string),s[1]):
%p A181868 for n from 3 to M do
%p A181868 a[n] := parse(s[n-1])/a[n-1];
%p A181868 s[n]:= cat(convert(a[n],string),s[n-1]);
%p A181868 end do:
%p A181868 seq(a[n],n = 1..M);
%Y A181868 A000032, A181754 - A181756, A181864 - A181870
%K A181868 nonn,easy
%O A181868 1,1
%A A181868 _Peter Bala_, Nov 28 2010