A176919 Triangle by columns: (1, 2, 3, ...) in each column interleaved with (0, 1, 2, ...) zeros. Columns > 1 shifted down twice.

1, 2, 0, 3, 1, 0, 4, 0, 0, 0, 5, 2, 1, 0, 0, 6, 0, 0, 0, 0, 0, 7, 3, 0, 1, 0, 0, 0, 8, 0, 2, 0, 0, 0, 0, 0, 9, 4, 0, 0, 1, 0, 0, 0, 0, 10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 11, 5, 3, 2, 0, 1, 0, 0, 0, 0, 0, 12, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Offset

1,2

Comments

Row sums of n-th row = A065608(n+1).

Links

Table of n, a(n) for n=1..78.

Formula

Triangle, left border = (1, 2, 3, ...). Each successive column is shifted down twice from previous column and interleaved with k zeros.

Example

First few rows of the triangle:
   1;
   2, 0;
   3, 1, 0;
   4, 0, 0, 0;
   5, 2, 1, 0, 0;
   6, 0, 0, 0, 0, 0;
   7, 3, 0, 1, 0, 0, 0;
   8, 0, 2, 0, 0, 0, 0, 0;
   9, 4, 0, 0, 1, 0, 0, 0, 0;
  10, 0, 0, 0, 0, 0, 0, 0, 0, 0;
  11, 5, 3, 2, 0, 1, 0, 0, 0, 0, 0;
  12, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0;
  13, 6, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0;
  14, 0, 4, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0;
  15, 7, 0, 3, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0;
  16, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0;
  17, 8, 5, 0, 0, 2, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0;
  18, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0;
  19, 9, 0, 4, 3, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0;
  ...

Crossrefs

Cf. A065608.

Sequence in context: A054372 A070679 A177443 * A220645 A127374 A098862

Adjacent sequences: A176916 A176917 A176918 * A176920 A176921 A176922

Keyword

nonn,tabl

Author

Gary W. Adamson & Mats Granvik, Apr 29 2010

Status

approved