A056647 Largest unitary square divisor of central binomial coefficient.

1, 1, 1, 1, 1, 4, 1, 1, 9, 36, 1, 4, 4, 1, 9, 9, 1, 4, 1, 4, 4, 1, 1, 4, 100, 25, 100, 25, 9, 144, 9, 9, 1, 4, 25, 100, 100, 25, 9, 36, 4, 1, 4, 1, 25, 400, 225, 900, 1764, 441, 196, 49, 49, 784, 4, 1, 1, 16, 1, 16, 16, 4, 441, 441, 49, 196, 49, 196, 36, 9, 1, 4, 4, 1, 100, 25, 1225

Offset

1,6

Links

Table of n, a(n) for n=1..77.

Formula

a(n) = A008833(A001405(n))/A055229(A001405(n))^2 = A056057(n)/A056059(n)^2.

Example

n=28: binomial(28,14) = 2*2*2*3*3*3*5*5*17*19*23. Its largest square divisor is 900, while a(28) = 900/6^2 = 25 is the unitary analog, the largest unitary square divisor.

Crossrefs

Cf. A000188, A001405, A008833, A055229, A056056, A056057, A056059.

Sequence in context: A243608 A219207 A157108 * A056057 A226234 A369189

Adjacent sequences: A056644 A056645 A056646 * A056648 A056649 A056650

Keyword

nonn

Author

Labos Elemer, Aug 09 2000

Status

approved