A067090 Floor(X/Y) where X = concatenation of (2n), (2n-1), ... down to n+1 and Y = concatenation of 1,2,3,... up to n.

2, 3, 5, 7, 8, 981, 114462, 13082645, 1471900839, 1635537203, 1799173568, 1962809933, 2126446298, 2290082663, 2453719028, 2617355393, 2780991758, 2944628123, 3108264488, 3271900853, 3435537218, 3599173583, 3762809948

Offset

1,1

Links

Table of n, a(n) for n=1..23.

Example

a(4) = floor(8765/1234) = 7.
a(6) = floor(121110987/123456) = floor(981.00527313374805598755832037325) = 981.

Mathematica

f[n_] := (k = 1; x = y = "0"; While[k < n + 1, x = StringJoin[x, ToString[2n - k + 1]]; y = StringJoin[y, ToString[2k - 1]]; k++ ]; Return[ Floor[ ToExpression[x] / ToExpression[y]]] ); Table[ f[n], {n, 1, 25} ]
Table[Floor[FromDigits[Flatten[IntegerDigits/@(Range[2n, n+1, -1])]]/FromDigits[Flatten[IntegerDigits/@(Range[n])]]], {n, 25}] (* Harvey P. Dale, Jul 24 2011 *)

Crossrefs

Cf. A067088, A067089.

Sequence in context: A105404 A238378 A075012 * A284173 A276227 A355269

Adjacent sequences: A067087 A067088 A067089 * A067091 A067092 A067093

Keyword

easy,base,nonn

Author

Amarnath Murthy, Jan 07 2002

Extensions

More terms from Robert G. Wilson v, Jan 09 2002

Edited by N. J. A. Sloane at the suggestion of Andrew S. Plewe, May 14 2007

Offset corrected by Sean A. Irvine, Dec 02 2023

Status

approved