A134237 Triangle read by rows, a(1) = 1, n-th row n terms of: (2n-1, 2n, 2n+1, ..., followed by n).

1, 3, 2, 5, 6, 3, 7, 8, 9, 4, 9, 10, 11, 12, 5, 11, 12, 13, 14, 15, 6, 13, 14, 15, 16, 17, 18, 7, 15, 16, 17, 18, 19, 20, 21, 8, 17, 18, 19, 20, 21, 22, 23, 24, 9, 19, 20, 21, 22, 23, 24, 25, 26, 27, 10, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 11, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 12

Offset

1,2

Comments

Row sums = A134238: (1, 5, 14, 28, 47, 71, 100, 134, ...).

Links

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

Example

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

Prog

(PARI) T(n, k) = if (k < n, (2*n-1) + (k-1), n);
tabl(nn) = for (n=1, nn, for (k=1, n, print1(T(n, k), ", ")); print); \\ Michel Marcus, Jul 13 2017

Crossrefs

Cf. A134238.

Sequence in context: A338470 A262395 A198755 * A341521 A227192 A360260

Adjacent sequences: A134234 A134235 A134236 * A134238 A134239 A134240

Keyword

nonn,tabl

Author

Gary W. Adamson, Oct 14 2007

Extensions

Corrected and extended by Michel Marcus, Jul 13 2017

Status

approved