A078925 Triangle of T1(n,m) = number of bracelets (necklaces that can be turned over) with m white beads and (2n+1-m) black ones, for 1<=m<=n.

1, 1, 2, 1, 3, 4, 1, 4, 7, 10, 1, 5, 10, 20, 26, 1, 6, 14, 35, 57, 76, 1, 7, 19, 56, 111, 185, 232, 1, 8, 24, 84, 196, 392, 600, 750, 1, 9, 30, 120, 324, 756, 1368, 2052, 2494, 1, 10, 37, 165, 507, 1353, 2829, 4950, 7105, 8524, 1, 11, 44, 220, 759, 2277, 5412, 10824

Offset

1,3

Comments

Left half of odd rows of table A052307 with left column deleted.

Links

Table of n, a(n) for n=1..63.

Index entries for sequences related to bracelets

Example

1; 1, 2; 1, 3, 4; 1, 4, 7, 10; ...

Mathematica

Table[ f[n, 2n + 1], {n, 11}] (* Robert G. Wilson v, Mar 29 2006 *)

Crossrefs

Cf. A052307 for full table, A073020 for even number of beads. Last term in each row gives A007123.

Sequence in context: A210555 A008949 A076832 * A361042 A072506 A188236

Adjacent sequences: A078922 A078923 A078924 * A078926 A078927 A078928

Keyword

nonn,tabl

Author

Thomas Hartinger (hartinger_t(AT)web.de), Dec 15 2002

Status

approved