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A261485
Number of set partitions of [n] into exactly nine parts such that no part contains two elements with a circular distance less than three.
2
1, 25, 385, 4675, 49192, 470470, 4205630, 35771452, 293015706, 2331292564, 18128195944, 138415310170, 1041422309315, 7742456506169, 57000743099267, 416275237530251, 3019814800297680, 21785468977120420, 156436446465306280, 1118973520631378880
OFFSET
9,2
LINKS
FORMULA
G.f.: -(5040*x^13 +5040*x^12 +5104*x^11 +18236*x^10 +7064*x^9 +10984*x^8 +4565*x^7 +3333*x^6 +1137*x^5 +527*x^4 +125*x^3 +39*x^2 +5*x+1) *x^9 / ((x-1) *(6*x-1) *(4*x-1) *(3*x-1) *(2*x-1) *(5*x-1) *(7*x-1) *(x+1) *(x^2+x+1) *(5*x^2+x+1) *(3*x^2+x+1) *(4*x^2+x+1) *(7*x^2+x+1) *(2*x^2+x+1) *(6*x^2+x+1)).
EXAMPLE
a(9) = 1: 1|2|3|4|5|6|7|8|9.
a(10) = 25: 14|2|3|5|6|7|8|9|10, 15|2|3|4|6|7|8|9|10, 1|25|3|4|6|7|8|9|10, 16|2|3|4|5|7|8|9|10, 1|26|3|4|5|7|8|9|10, 1|2|36|4|5|7|8|9|10, 17|2|3|4|5|6|8|9|10, 1|27|3|4|5|6|8|9|10, 1|2|37|4|5|6|8|9|10, 1|2|3|47|5|6|8|9|10, 18|2|3|4|5|6|7|9|10, 1|28|3|4|5|6|7|9|10, 1|2|38|4|5|6|7|9|10, 1|2|3|48|5|6|7|9|10, 1|2|3|4|58|6|7|9|10, 1|29|3|4|5|6|7|8|10, 1|2|39|4|5|6|7|8|10, 1|2|3|49|5|6|7|8|10, 1|2|3|4|59|6|7|8|10, 1|2|3|4|5|69|7|8|10, 1|2|3,10|4|5|6|7|8|9, 1|2|3|4,10|5|6|7|8|9, 1|2|3|4|5,10|6|7|8|9, 1|2|3|4|5|6,10|7|8|9, 1|2|3|4|5|6|7,10|8|9.
CROSSREFS
Column k=9 of A261477.
Sequence in context: A094190 A069396 A228216 * A125482 A306322 A344733
KEYWORD
nonn,easy
AUTHOR
Alois P. Heinz, Aug 20 2015
STATUS
approved