A128306 Triangle read by rows: A054521 * A007318 as infinite lower triangular matrices.

1, 1, 0, 2, 1, 0, 2, 2, 1, 0, 4, 6, 4, 1, 0, 2, 4, 6, 4, 1, 0, 6, 15, 20, 15, 6, 1, 0, 4, 12, 22, 24, 16, 6, 1, 0, 6, 21, 45, 60, 51, 27, 8, 1, 0, 4, 16, 44, 76, 85, 62, 29, 8, 1, 0, 10, 45, 120, 210, 252, 210, 120, 45, 10, 1, 0, 4, 20, 66, 144, 226, 258, 211, 120, 45, 10, 1, 0

Offset

1,4

Comments

Left border = phi(n), A000010: (1, 1, 2, 2, 4, 2, 6, ...). Row sums = A054432: (1, 1, 3, 5, 15, 17, 63, ...).

Links

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

Example

First few rows of the triangle:
  1;
  1,  0;
  2,  1,  0;
  2,  2,  1,  0;
  4,  6,  4,  1,  0;
  2,  4,  6,  4,  1,  0;
  6, 15, 20, 15,  6,  1,  0;
  ...

Crossrefs

Cf. A000010, A007318, A054432, A054521.

Sequence in context: A212957 A035393 A068913 * A372626 A305152 A170983

Adjacent sequences: A128303 A128304 A128305 * A128307 A128308 A128309

Keyword

nonn,tabl

Author

Gary W. Adamson, Feb 25 2007

Extensions

Definition amended and terms starting at a(56) corrected by Georg Fischer, May 29 2023

Status

approved