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A052837
Number of partitions of 2n whose Ferrers-Young diagram allows more than one different domino tiling.
3
0, 0, 1, 4, 10, 22, 43, 80, 141, 240, 397, 640, 1011, 1568, 2395, 3604, 5360, 7876, 11460, 16510, 23588, 33418, 47006, 65640, 91085, 125596, 172215, 234820, 318579, 430060, 577920, 773130, 1030007, 1366644, 1806445, 2378892, 3121835, 4082796, 5322360, 6916360
OFFSET
0,4
COMMENTS
The original name was: A simple grammar.
FORMULA
G.f.: (exp(Sum_{j>=1} -x^j/((x^j-1)*j) )-1)^2.
a(n) = Sum_{k>=2} A304789(n,k). - Alois P. Heinz, May 26 2018
MAPLE
spec := [S, {C=Sequence(Z, 1 <= card), B=Set(C, 1 <= card), S=Prod(B, B)}, unlabeled]: seq(combstruct[count](spec, size=n), n=0..20);
# second Maple program:
a:= n-> (p-> add(p(j)*p(n-j), j=1..n-1))(combinat[numbpart]):
seq(a(n), n=0..40); # Alois P. Heinz, May 26 2018
CROSSREFS
Essentially the same as A048574.
Sequence in context: A034357 A023626 A048574 * A052821 A292445 A023628
KEYWORD
easy,nonn
AUTHOR
encyclopedia(AT)pommard.inria.fr, Jan 25 2000
EXTENSIONS
More terms from Franklin T. Adams-Watters, Feb 08 2006
New name from Alois P. Heinz, May 26 2018
STATUS
approved