A067121 a(n) = floor[X/Y] where X = the concatenation of the first n even numbers in increasing order and Y = their sum.

1, 4, 20, 123, 8227, 587643, 44073235, 3427918353, 274233468240, 22437283765107, 1869773647092288, 158211616292424373, 13560995682207803419, 1175286292458009629726, 102837550590075842601095

Offset

1,2

Links

Harvey P. Dale, Table of n, a(n) for n = 1..352

Example

a(4): floor[2468/(2+4+6+8)] = floor[123.4] = 123.

Maple

for i from 1 to 33 do n := 2*i:s := n:c := n:n := n-2:while(n>0) do s := s+n:g := floor(log(c+1)/log(10)):c := c+10^(g+1)*n:n := n-2:end do:a[i] := floor(c/s):end do:q := seq(a[j], j=1..33);

Mathematica

Module[{nn=20, ev}, ev=2*Range[nn]; Table[Floor[FromDigits[Flatten[ IntegerDigits/@ Take[ev, n]]]/(n^2+n)], {n, nn}]] (* Harvey P. Dale, Dec 05 2014 *)

Crossrefs

Cf. A067112-A067120.

Sequence in context: A121553 A067116 A347339 * A002793 A162509 A371524

Adjacent sequences: A067118 A067119 A067120 * A067122 A067123 A067124

Keyword

easy,nonn,base

Author

Amarnath Murthy, Jan 08 2002

Extensions

More terms from Sascha Kurz, Mar 23 2002

Status

approved