A274874 Number of set partitions of [n] into exactly ten blocks such that all odd elements are in blocks with an odd index and all even elements are in blocks with an even index.

1, 5, 95, 475, 5294, 26470, 227294, 1136470, 8351711, 41758555, 277114769, 1385573845, 8568214932, 42841074660, 251848578952, 1259242894760, 7132223195725, 35661115978625, 196428153720067, 982140768600335, 5296485323226634, 26482426616133170

Offset

10,2

Links

Alois P. Heinz, Table of n, a(n) for n = 10..1000

Formula

G.f.: -x^10/((x-1)*(4*x+1)*(3*x-1)*(5*x-1)*(2*x+1)*(2*x-1)*(3*x+1)*(4*x-1)*(x+1)*(12*x^2-1)*(6*x^2-1)*(20*x^2-1)*(2*x^2-1)).

Example

a(10) = 1: 1|2|3|4|5|6|7|8|9|(10).
a(11) = 5: 1(11)|2|3|4|5|6|7|8|9|(10), 1|2|3(11)|4|5|6|7|8|9|(10), 1|2|3|4|5(11)|6|7|8|9|(10), 1|2|3|4|5|6|7(11)|8|9|(10), 1|2|3|4|5|6|7|8|9(11)|(10).

Crossrefs

Column k=10 of A274537.

Sequence in context: A116159 A054205 A116290 * A275292 A362481 A359271

Adjacent sequences: A274871 A274872 A274873 * A274875 A274876 A274877

Keyword

nonn,easy

Author

Alois P. Heinz, Jul 09 2016

Status

approved