A110395 - OEIS

%I #22 Sep 22 2015 08:20:02

%S 1,18,246,3016,34920,390480,4266640,45866880,487198080,5128019200,

%T 53591788800,556898534400,5760319052800,59355533260800,

%U 609667001088000,6245327982592000,63829424295936000,651070362673152000,6629663109210112000,67406737815797760000

%N a(1) = 1. a(n) = n times (10's complement of a(n-1)).

%C a(1)=1; a(n)=n*[10...0 - a(n-1)] for n>1 (00...0 and a[n-1] have the same number of digits). - _Emeric Deutsch_, Jul 31 2005

%H Sidney Cadot, <a href="/A110395/b110395.txt">Table of n, a(n) for n = 1..200</a>

%e a(4) = 4* 10's complement of a(3) = 4*(1000-246) = 3016.

%p s:=proc(m) nops(convert(m,base,10)) end: a[1]:=1: for n from 2 to 21 do a[n]:=n*(10^s(a[n-1])-a[n-1]) od: seq(a[n],n=1..21); # _Emeric Deutsch_, Jul 31 2005

%p # second Maple program:

%p a:= proc(n) option remember; `if`(n<2, n,

%p        n*(p-> 10^length(p)-p)(a(n-1)))

%p     end:

%p seq(a(n), n=1..25);  # _Alois P. Heinz_, Sep 22 2015

%t a110395[numTerms_] := Block[{complement, a},

%t    complement[n_] := 10^IntegerLength[n] - n;

%t    a[n_] := a[n] = If[n == 1, 1, n*complement[a[n - 1]]];

%t    Table[a[n], {n, 1, numTerms}

%t ]];(* _Sidney Cadot_, Sep 22 2015 *)

%t a110395[50]

%Y Cf. A110394.

%K base,easy,nonn

%O 1,2

%A _Amarnath Murthy_, Jul 29 2005

%E More terms from _Emeric Deutsch_, Jul 31 2005

%E Incorrect formula and corresponding Mathematica program removed by _Sidney Cadot_, Sep 22 2015