A174856 Square array read by antidiagonals up. Redheffer type matrix. T(1,1)=1 and T(n,1) = A049240.

1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0, 1, 1, 0, 0, 0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1

Offset

1,1

Comments

The first column is equal to 0 when n is a square greater than 1. The rest of the array is equal to A143104. The determinant of this array is A002819.

Links

Table of n, a(n) for n=1..105.

Example

The array begins:
  1,1,1,1,1,1,1,1,1,1
  1,1,0,0,0,0,0,0,0,0
  1,0,1,0,0,0,0,0,0,0
  0,1,0,1,0,0,0,0,0,0
  1,0,0,0,1,0,0,0,0,0
  1,1,1,0,0,1,0,0,0,0
  1,0,0,0,0,0,1,0,0,0
  1,1,0,1,0,0,0,1,0,0
  0,0,1,0,0,0,0,0,1,0
  1,1,0,0,1,0,0,0,0,1

Mathematica

t[1, 1] = 1; t[n_, 1] := Boole[!IntegerQ[Sqrt[n]]]; t[n_, k_] := Boole[n == 1 || Mod[n, k] == 0]; Table[t[n - k + 1, k], {n, 1, 14}, {k, 1, n}] // Flatten (* Jean-François Alcover, Dec 05 2013 *)

Crossrefs

Cf. A143104, A002819, A174854, A174852.

Sequence in context: A127247 A144778 A143142 * A175608 A285467 A194679

Adjacent sequences: A174853 A174854 A174855 * A174857 A174858 A174859

Keyword

nonn,tabl

Author

Mats Granvik, Mar 31 2010

Status

approved