login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A067118
a(n) =floor[X/Y] where X= concatenation of first n even numbers in decreasing order and Y = that of first n odd numbers in increasing order.
1
2, 3, 4, 6, 8, 8, 10, 11, 13, 14, 16, 17, 19, 20, 22, 23, 25, 26, 28, 29, 31, 32, 34, 35, 37, 38, 40, 41, 43, 44, 46, 47, 49, 50, 52, 53, 55, 56, 58, 59, 60, 62, 63, 65, 66, 68, 69, 71, 72, 74, 75, 76, 78, 79, 81, 82, 84, 85, 86, 88, 89, 91, 92, 94, 95, 97, 98, 100, 101, 103
OFFSET
1,1
EXAMPLE
a(4) = floor[8642/1357] = floor[6.368...] = 6.
MAPLE
for i from 1 to 50 do c := 2:n := 4:m := 2*i-1:d := m:m := m-2:while(m>0) do g := floor(log(c+1)/log(10)):c := c+10^(g)*n:n := n+2:g := floor(log(d)/log(10)): d := d+10^(g+1)*m:m := m-2:end do:a[i] := floor(c/d):end do:q := seq(a[j], j=1..50);
MATHEMATICA
Table[Floor[FromDigits[Flatten[IntegerDigits/@Range[2n, 2, -2]]]/FromDigits[ Flatten[IntegerDigits/@Range[1, 2n-1, 2]]]], {n, 80}] (* Harvey P. Dale, Nov 02 2013 *)
CROSSREFS
KEYWORD
easy,nonn,base
AUTHOR
Amarnath Murthy, Jan 08 2002
EXTENSIONS
More terms from Sascha Kurz, Mar 23 2002
Edited by Charles R Greathouse IV, Apr 27 2010
STATUS
approved