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 A056886 Determinant of the n X n Hankel matrix whose entries are s_2 (i+j), 0 <= i, j < n, where s_2 is the sum of the base-2 bits. 2
 1, 0, -1, 2, 5, -8, 3, 8, 141, -204, 11, -4, -11, -30, 99, 1836, 164997, -224532, 2403, -126, -39, 14, -5, -14, -267, -738, 351, -1134, -28431, -538002, 9537507, 891167508, 361226647845, -471103550820, 1127461923, -11787930, -675783, 34992, -1377, -432, -927 (list; graph; refs; listen; history; text; internal format)
 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 Sequence in context: A220398 A200225 A258749 * A197839 A021391 A162611 Adjacent sequences:  A056883 A056884 A056885 * A056887 A056888 A056889 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

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Last modified September 16 20:51 EDT 2021. Contains 347473 sequences. (Running on oeis4.)