OFFSET
0,4
COMMENTS
Hankel transform of A000120.
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..350
EXAMPLE
a(2) = -1 because det [[0,1],[1,1]] = -1.
MAPLE
with(LinearAlgebra):
wt:= proc(n) local m, t; m:=n; t:=0;
while m>0 do t:= t+irem(m, 2, 'm') od; t
end:
a:= n-> Determinant(Matrix(n, (i, j)-> wt(i+j-2))):
seq(a(n), n=0..40); # Alois P. Heinz, May 25 2013
MATHEMATICA
a[n_] := Det[Array[DigitCount[#1 + #2 - 2, 2, 1]&, {n, n}]]; a[0] = 1;
a /@ Range[0, 40] (* Jean-François Alcover, Nov 10 2020 *)
PROG
(PARI) {a(n) = if( n<0, 0, matdet( matrix( n, n, i, j, 2*i + 2*j - 4 - valuation( (2*i + 2*j - 4)!, 2))))} /* Michael Somos, Feb 08 2011 */
CROSSREFS
KEYWORD
sign,look
AUTHOR
Jeffrey Shallit, Sep 04 2000
EXTENSIONS
a(0)=1 added by Michael Somos, Feb 08 2011
More terms from Alois P. Heinz, May 25 2013
STATUS
approved