A127805 Inverse of number triangle A(n,k) = 1/((10*10^n-1)/9) if k <= n <= 2k, 0 otherwise.

1, 0, 11, 0, -11, 111, 0, 11, -111, 1111, 0, 0, 0, -1111, 11111, 0, -11, 111, 0, -11111, 111111, 0, 0, 0, 0, 0, -111111, 1111111, 0, 11, -111, 1111, 0, 0, -1111111, 11111111, 0, 0, 0, 0, 0, 0, 0, -11111111, 111111111

Offset

0,3

Comments

Row sums are A127806.

Links

Table of n, a(n) for n=0..44.

Example

Triangle begins
  1;
  0, 11;
  0, -11, 111;
  0, 11, -111, 1111;
  0, 0, 0, -1111, 11111;
  0, -11, 111, 0, -11111, 111111;
  0, 0, 0, 0, 0, -111111, 1111111;
  0, 11, -111, 1111, 0, 0, -1111111, 11111111;
  0, 0, 0, 0, 0, 0, 0, -11111111, 111111111;
  0, 0, 0, -1111, 11111, 0, 0, 0, -111111111, 1111111111;
  0, 0, 0, 0, 0, 0, 0, 0, 0, -1111111111, 11111111111;
Triangle is inverse of
  1;
  0, 1/11;
  0, 1/111, 1/111;
  0, 0, 1/1111, 1/1111;
  0, 0, 1/11111, 1/11111, 1/11111;
  0, 0, 0, 1/111111, 1/111111, 1/111111;
  0, 0, 0, 1/1111111, 1/1111111, 1/1111111, 1/1111111;
  0, 0, 0, 0, 1/11111111, 1/11111111, 1/11111111, 1/11111111;
  0, 0, 0, 0, 1/111111111, 1/111111111, 1/111111111, 1/111111111, 1/111111111;

Crossrefs

Sequence in context: A348006 A338827 A055963 * A256480 A088621 A088623

Adjacent sequences: A127802 A127803 A127804 * A127806 A127807 A127808

Keyword

sign,tabl

Author

Paul Barry, Jan 29 2007

Status

approved