A161780 Square array read by antidiagonals up. Redheffer type matrix. A007427 interleaved with k-1 zeros in the columns.

1, -2, 1, -2, 1, 1, 1, 0, 0, 1, -2, -2, 1, 0, 1, 4, 0, 0, 0, 0, 1, -2, -2, 0, 1, 0, 0, 1, 0, 0, -2, 0, 0, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 0, 1, 4, 0, 0, 0, 0, 0, 0, 0, 0, 1, -2, -2, -2, -2, 0, 1, 0, 0, 0, 0, 1, -2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -2, 4, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 4, 0, 1

Offset

1,2

Comments

The determinant of this matrix is A006218.

Links

Table of n, a(n) for n=1..94.

Example

Table begins:
..1..1..1..1..1..1..1..1
.-2..1..0..0..0..0..0..0
.-2..0..1..0..0..0..0..0
..1.-2..0..1..0..0..0..0
.-2..0..0..0..1..0..0..0
..4.-2.-2..0..0..1..0..0
.-2..0..0..0..0..0..1..0
..0..1..0.-2..0..0..0..1

Prog

(Excel) =if(row()=1; 1; if(mod(row(); column())=0; 1*lookup(row()/column(); A000027; A007427); 0))

Crossrefs

Cf. A007427, A006218, A002321.

Sequence in context: A344569 A341094 A346831 * A136571 A178562 A232624

Adjacent sequences: A161777 A161778 A161779 * A161781 A161782 A161783

Keyword

sign,tabl

Author

Mats Granvik, Jun 19 2009

Status

approved