A127701 Infinite lower triangular matrix with (1, 2, 3, ...) in the main diagonal, (1, 1, 1, ...) in the subdiagonal and the rest zeros.

1, 1, 2, 0, 1, 3, 0, 0, 1, 4, 0, 0, 0, 1, 5, 0, 0, 0, 0, 1, 6, 0, 0, 0, 0, 0, 1, 7, 0, 0, 0, 0, 0, 0, 1, 8, 0, 0, 0, 0, 0, 0, 0, 1, 9, 0, 0, 0, 0, 0, 0, 0, 0, 1, 10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 11, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 12, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 13, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Offset

1,3

Comments

Eigensequence of the triangle = A001040 starting (1, 3, 10, 43, 225, ...). - Gary W. Adamson, Dec 29 2008

Links

Table of n, a(n) for n=1..103.

Example

First few rows of the triangle are:
  1;
  1, 2;
  0, 1, 3;
  0, 0, 1, 4;
  0, 0, 0, 1, 5;
  0, 0, 0, 0, 1, 6;
  0, 0, 0, 0, 0, 1, 7;
  ...

Mathematica

Join[{1}, Flatten[Table[Join[{PadRight[{}, n-2, 0], 1, n}], {n, 2, 15}]]] (* Harvey P. Dale, Jan 06 2014 *)

Crossrefs

Cf. A001040. - Gary W. Adamson, Dec 29 2008

Sequence in context: A280500 A309576 A128132 * A158821 A004199 A062283

Adjacent sequences: A127698 A127699 A127700 * A127702 A127703 A127704

Keyword

nonn,easy,tabl

Author

Gary W. Adamson, Jan 23 2007

Extensions

More terms from Jon E. Schoenfield, May 26 2007

Status

approved