A134249 Triangle read by rows, taken from the lower triangular matrix (M * A000012 + A000012 * M) - A000012; where M = lower triangular matrix with (1,1,1,...) in the main diagonal and the triangular numbers in the subdiagonal and A000012 = (1; 1,1; 1,1,1; ...).

1, 3, 1, 5, 7, 1, 8, 10, 13, 1, 12, 14, 17, 21, 1, 17, 19, 22, 26, 31, 1, 23, 25, 28, 32, 37, 43, 1, 30, 32, 35, 39, 44, 50, 57, 1, 38, 40, 43, 47, 52, 58, 65, 73, 1, 47, 49, 52, 56, 61, 67, 74, 82, 91, 1

Offset

1,2

Comments

Row sums = A037235: (1, 4, 13, 32, 65, 116, ...). Left column = A134250: (1, 3, 5, 8, 12, 17, 23, ...).

Links

Table of n, a(n) for n=1..55.

Example

First few rows of the triangle:
   1;
   3,  1;
   5,  7,  1;
   8, 10, 13,  1;
  12, 14, 17, 21,  1;
  17, 19, 22, 26, 31,  1;
  23, 25, 28, 32, 37, 43,  1;
  ...

Crossrefs

Cf. A037235, A134250.

Sequence in context: A201552 A216182 A143524 * A188509 A265707 A360965

Adjacent sequences: A134246 A134247 A134248 * A134250 A134251 A134252

Keyword

nonn,tabl

Author

Gary W. Adamson, Oct 15 2007

Extensions

Edited by N. J. A. Sloane, Nov 01 2009

Status

approved