A072500 Product of divisors of n which are >= n^(1/2).

1, 2, 3, 8, 5, 18, 7, 32, 27, 50, 11, 288, 13, 98, 75, 512, 17, 972, 19, 1000, 147, 242, 23, 13824, 125, 338, 243, 2744, 29, 27000, 31, 4096, 363, 578, 245, 419904, 37, 722, 507, 64000, 41, 86436, 43, 10648, 6075, 1058, 47, 1769472, 343, 12500, 867, 17576, 53

Offset

1,2

Comments

a(n) = n iff n is not a composite number.

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Example

The divisors of 20 are 1, 2, 4, 5, 10 and 20. a(20) = 5*10*20= 1000.

Mathematica

Table[Times @@ Select[Divisors[n], # >= Sqrt[n] &], {n, 1, 55}]

Crossrefs

Cf. A072499, A072501 & A070038.

Sequence in context: A070935 A095164 A075384 * A376014 A208449 A346957

Adjacent sequences: A072497 A072498 A072499 * A072501 A072502 A072503

Keyword

nonn

Author

Amarnath Murthy, Jul 20 2002

Extensions

Edited by Robert G. Wilson v, Jul 22 2002

Corrected a(16) by Harvey P. Dale, Oct 06 2011

Status

approved