A168078 Number of matrices with elements 1..n in which every pair of adjacent elements are relatively prime

1, 4, 12, 32, 144, 176, 1728, 4320, 27936

Offset

1,2

Comments

For prime p, a(p) = 2*A076220(p)

Links

Table of n, a(n) for n=1..9.

Lior Manor, Illustration of initial terms

Crossrefs

Cf. A000005, A076220

Sequence in context: A066536 A265212 A295500 * A225894 A318637 A227554

Adjacent sequences: A168075 A168076 A168077 * A168079 A168080 A168081

Keyword

more,nonn

Author

Lior Manor, Nov 18 2009

Status

approved