A131245 A046854^2 as an infinite lower triangular matrix.

1, 2, 1, 3, 2, 1, 5, 5, 2, 1, 8, 9, 7, 2, 1, 13, 19, 13, 9, 2, 1, 21, 33, 34, 17, 11, 2, 1, 34, 65, 61, 53, 21, 13, 2, 1, 55, 111, 141, 97, 76, 25, 15, 2, 1, 89, 210, 248, 257, 141, 103, 29, 17, 2, 1, 144, 355, 534, 461, 421, 193, 134, 33, 19, 2, 1

Offset

0,2

Comments

Left border = Fibonacci numbers.

Row sums = A131246.

A131243 is the square of the reflection triangle to A046854: A065941.

Row sums of A131243 = (1, 3, 6, 14, 30, 67, 146, 322, 705, 1549, ...).

Links

Table of n, a(n) for n=0..65.

Example

First few rows of the triangle:
   1;
   2,  1;
   3,  2,  1;
   5,  5,  2,  1;
   8,  9,  7,  2,  1;
  13, 19, 13,  9,  2,  1;
  21, 33, 34, 17, 11,  2,  1;
  ...

Prog

(PARI) T(n, k) = binomial((n+k)\2, k);
row(n) = my(m=matrix(n+1, n+1, i, j, T(i-1, j-1))); vector(n+1, i, (m^2)[n+1, i]);
lista(nn) = for (n=0, nn, my(v=row(n)); for (i=1, #v, print1(v[i], ", ")); ); \\ Michel Marcus, Feb 28 2022

Crossrefs

Cf. A131243, A131244, A131246, A046854, A065941.

Sequence in context: A131243 A038497 A091355 * A179927 A104446 A131345

Adjacent sequences: A131242 A131243 A131244 * A131246 A131247 A131248

Keyword

nonn,tabl

Author

Gary W. Adamson, Jun 22 2007

Extensions

More terms from Michel Marcus, Feb 28 2022

Status

approved