A130270 Triangle read by rows, T(n) followed by 1, 2, 3, ..., n-1.

1, 3, 1, 6, 1, 2, 10, 1, 2, 3, 15, 1, 2, 3, 4, 21, 1, 2, 3, 4, 5, 28, 1, 2, 3, 4, 5, 6, 36, 1, 2, 3, 4, 5, 6, 7, 45, 1, 2, 3, 4, 5, 6, 7, 8

Offset

1,2

Comments

Row sums = n^2.

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Formula

Triangle read by rows, T(n) followed by 1,2,3,...,n-1. Row differences of triangle A130269 starting from the left.

Example

First few rows of the triangle:
   1;
   3, 1;
   6, 1, 2;
  10, 1, 2, 3;
  15, 1, 2, 3, 4;
  ...
Row 4 = (10, 1, 2, 3) = differences of row 4 of A130269: (10, 11, 13, 16).

Mathematica

Table[Join[{(n(n+1))/2, Range[n-1]}], {n, 10}]//Flatten (* Harvey P. Dale, Dec 31 2021 *)

Crossrefs

Cf. A000217, A130269.

Sequence in context: A098076 A171852 A010287 * A225599 A090049 A115364

Adjacent sequences: A130267 A130268 A130269 * A130271 A130272 A130273

Keyword

nonn,tabl

Author

Gary W. Adamson, May 18 2007

Status

approved