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A338397 Triangle read by rows: T(n,m)= Sum_{k=0..m/2} C(n-k,m-2*k)*C(n-k,m-k)*C(n,k))/C(2*k,k). 0
1, 1, 1, 1, 4, 2, 1, 9, 12, 4, 1, 16, 42, 34, 8, 1, 25, 110, 160, 90, 16, 1, 36, 240, 550, 540, 226, 32, 1, 49, 462, 1540, 2310, 1666, 546, 64, 1, 64, 812, 3724, 7910, 8596, 4802, 1282, 128, 1, 81, 1332, 8064, 23058, 34986, 29190, 13140, 2946, 256 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,5

LINKS

Table of n, a(n) for n=0..54.

FORMULA

G.f.: A008459(x,y)/(1-(x*y*A008459(x,y))^2).

EXAMPLE

1,

1, 1,

1, 4, 2,

1, 9, 12, 4,

1, 16, 42, 34, 8,

1, 25, 110, 160, 90, 16,

1, 36, 240, 550, 540, 226, 32

PROG

(Maxima)

T(n, m):=sum((binomial(n-k, m-2*k)*binomial(n-k, m-k)*binomial(n, k))/binomial(2*k, k) , k, 0, m/2);

CROSSREFS

Cf. A001263, A008459, A176280 (row sums), A338372.

Sequence in context: A208612 A183157 A211957 * A063983 A259985 A144084

Adjacent sequences:  A338394 A338395 A338396 * A338398 A338399 A338400

KEYWORD

nonn,tabl

AUTHOR

Vladimir Kruchinin, Oct 23 2020

STATUS

approved

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Last modified May 12 06:20 EDT 2021. Contains 343814 sequences. (Running on oeis4.)