1,4

Eric Weisstein's World of Mathematics, Circulant Matrix.

a(4) = -5 because of the determinant -5 =

|1,1,1,2|

|2,1,1,1|

|1,2,1,1|

|1,1,2,1|.

a(11) = 6076067 = determinant

|1, 1, 1, 2, 1, 2, 1, 5, 2, 2, 1|

|1, 1, 1, 1, 2, 1, 2, 1, 5, 2, 2|

|2, 1, 1, 1, 1, 2, 1, 2, 1, 5, 2|

|2, 2, 1, 1, 1, 1, 2, 1, 2, 1, 5|

|5, 2, 2, 1, 1, 1, 1, 2, 1, 2, 1|

|1, 5, 2, 2, 1, 1, 1, 1, 2, 1, 2|

|2, 1, 5, 2, 2, 1, 1, 1, 1, 2, 1|

|1, 2, 1, 5, 2, 2, 1, 1, 1, 1, 2|

|2, 1, 2, 1, 5, 2, 2, 1, 1, 1, 1|

|1, 2, 1, 2, 1, 5, 2, 2, 1, 1, 1|

|1, 1, 2, 1, 2, 1, 5, 2, 2, 1, 1|.

Cf. A000001, A048954, A052182, A066933, A086459, A086569.

Adjacent sequences: A118709 A118710 A118711 this_sequence A118713 A118714 A118715

Sequence in context: A019071 A028285 A007430 this_sequence A130878 A104422 A026547

easy,sign

Jonathan Vos Post (jvospost2(AT)yahoo.com), May 20 2006