A067089 - OEIS

A067089

Floor(X/Y) where X = concatenation of (2n), (2n-1), ... down to n+1 and Y = concatenation of n, n-1, n-2, ... down to 1.

%I #11 Dec 02 2023 23:17:13

%S 2,2,2,2,2,185,18461,1842626,183987603,1837682236,1999303871,

%T 2000827643,2000777468,2000722020,2000673854,2000631711,2000594530,

%U 2000561482,2000531914,2000505305,2000481231,2000459347,2000439367

%N Floor(X/Y) where X = concatenation of (2n), (2n-1), ... down to n+1 and Y = concatenation of n, n-1, n-2, ... down to 1.

%e a(6) = floor(121110987/654321) = floor(185.094146451053840546153951959359) = 185.

%t f[n_] := (k = 1; x = y = "0"; While[k < n + 1, x = StringJoin[x, ToString[2n - k + 1]]; y = StringJoin[ToString[2k - 1], y]; k++ ]; Return[ Floor[10* ToExpression[x] / ToExpression[y]]] ); Table[ f[n], {n, 1, 25} ]

%t fd[st_,en_]:=FromDigits[Flatten[IntegerDigits/@Range[st,en,-1]]]; Table[ Floor[fd[2n,n+1]/fd[n,1]],{n,30}] (* _Harvey P. Dale_, Jul 04 2013 *)

%Y Cf. A067088.

%K easy,base,nonn

%O 1,1

%A _Amarnath Murthy_, Jan 07 2002

%E More terms from _Robert G. Wilson v_, Jan 09 2002

%E Offset corrected by _Sean A. Irvine_, Dec 02 2023