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A056647 Largest unitary square divisor of central binomial coefficient. 0
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 (list; graph; refs; listen; history; text; internal format)
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 A185027

Adjacent sequences:  A056644 A056645 A056646 * A056648 A056649 A056650

KEYWORD

nonn

AUTHOR

Labos Elemer, Aug 09 2000

STATUS

approved

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Last modified January 26 11:20 EST 2020. Contains 331279 sequences. (Running on oeis4.)