A186245 a(n) = binomial(n^2, 2*n).

1, 84, 12870, 3268760, 1251677700, 675248872536, 488526937079580, 456703981505085600, 535983370403809682970, 771629762387959506903300, 1337261858854117218288723600, 2746379593275133584459064976784, 6596095888094645606758451183394760

Offset

2,2

Links

Michael De Vlieger, Table of n, a(n) for n = 2..205

Mathematica

Array[Binomial[#^2, 2 #] &, 13, 2] (* Michael De Vlieger, May 21 2021 *)

Prog

(Python)
import math
for n in range(2, 22):
    x = n*n
    y = n+n
    print(math.factorial(x) / (math.factorial(x-y) * math.factorial(y)), end=', ')

Crossrefs

Cf. A014062.

Sequence in context: A283947 A265586 A278725 * A224429 A289325 A202923

Adjacent sequences: A186242 A186243 A186244 * A186246 A186247 A186248

Keyword

nonn

Author

Alex Ratushnyak, Aug 18 2012

Status

approved