A127738 Triangle read by rows: the matrix product A004736 * A127701 of two triangular matrices.

1, 3, 2, 5, 5, 3, 7, 8, 7, 4, 9, 11, 11, 9, 5, 11, 14, 15, 14, 11, 6, 13, 17, 19, 19, 17, 13, 7, 15, 20, 23, 24, 23, 20, 15, 8, 17, 23, 27, 29, 29, 27, 23, 17, 9, 19, 26, 31, 34, 35, 34, 31, 26, 19, 10

Offset

1,2

Comments

Left column = A028387: (1, 5, 11, 19, 29, 41, 55, ...).

Links

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

Formula

T(n,k) = Sum_{j=k..n) A004736(n,j)*A127701(j,k). - R. J. Mathar, Aug 31 2022

T(n,k) = k+(k+1)*(n-k) = n+k*(n-k) = n +A094053(n,k) = A059036(n,k). - R. J. Mathar, Aug 31 2022

Example

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

Crossrefs

Cf. A004736, A127701, A008778 (row sums), A028387.

Sequence in context: A094787 A132778 A182289 * A350900 A001598 A141297

Adjacent sequences: A127735 A127736 A127737 * A127739 A127740 A127741

Keyword

nonn,tabl,easy

Author

Gary W. Adamson, Jan 27 2007

Status

approved