A260909 Denominator of 1/det(M) where M is the n X n matrix with M[i,j] = 1/gcd(i,j).

1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 4, 4, 32, 2, 32, 32, 64, 64, 256, 256, 512, 128, 512, 1024, 2048, 1024, 4096, 16384, 32768, 1024, 4096, 32768, 262144, 131072, 524288, 524288, 4194304, 2097152, 16777216, 33554432, 67108864, 33554432, 268435456, 268435456

Offset: 1

Author

Robert G. Wilson v, Aug 04 2015

Keywords

• nonn

Comments

All terms are powers of two (A000079).

Crossrefs

Cf. A000079, A260897, A260908.

Programs

Maple

seq(denom(1/LinearAlgebra:-Determinant(Matrix(n,n,1/igcd))),n=1..100); # Robert Israel, Aug 16 2015

Mathematica

f[n_] := 1/Det[ Table[ 1/GCD[i, j], {i, n}, {j, n}]]; Denominator@ Array[f, 46]

PARI

vector(50, n, denominator(1/matdet(matrix(n, n, i, j, 1/gcd(i, j))))) \\ Michel Marcus, Aug 07 2015