1,1

Eric Weisstein's World of Mathematics, Circulant Matrix.

a(4) = 0 because of the singular matrix:

[2, 1, 3, 4]

[4, 2, 1, 3]

[3, 4, 2, 1]

[1, 3, 4, 2].

Determinant of matrix, for n = 8, is 348940406250 =

| 2, 1, 3, 4, 7, 11, 18, 29 |

| 1, 3, 4, 7, 11, 18, 29, 2 |

| 3, 4, 7, 11, 18, 29, 2, 1 |

| 4, 7, 11, 18, 29, 2, 1, 3 |

| 7, 11, 18, 29, 2, 1, 3, 4 |

| 11, 18, 29, 2, 1, 3, 4, 7 |

| 18, 29, 2, 1, 3, 4, 7, 11 |

| 29, 2, 1, 3, 4, 7, 11, 29 |

A000032 Lucas numbers (beginning at 2): L(n) = L(n-1) + L(n-2). A048954 Wendt determinant of n-th circulant matrix C(n). A052182 Circulant of natural numbers. A066933 Circulant of prime numbers. A086459 Circulant of powers of 2.

Cf. A000032, A048954, A052182, A066933, A086459, A086569.

Sequence in context: A041383 A042903 A132534 this_sequence A073524 A130226 A032808

Adjacent sequences: A118699 A118700 A118701 this_sequence A118703 A118704 A118705

easy,sign

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