A245530 a(n) = smallest square which is the product of a minimal set of distinct numbers not less than n.

1, 36, 144, 4, 400, 576, 784, 14400, 9, 32400, 4356, 3600, 6084, 1587600, 129600, 16, 10404, 11664, 23104, 14400, 15876, 17424, 33856, 20736, 25, 876096, 25401600, 1254400, 53824, 44100, 61504, 57600, 85377600, 4161600, 2822400, 36, 136900, 116964, 97344

Offset: 1

Author

Reinhard Zumkeller, Jul 25 2014

Keywords

• nonn

Comments

a(n) mod n = 0; a(n) mod A006255(n) = 0.

Links

• Peter Kagey, Table of n, a(n) for n = 1..1000 (First 125 terms from Reinhard Zumkeller)

Crossrefs

Cf. A006255, A066400, A066401, A245499.

Programs

Haskell

a245530 = product . a245499_row

Mathematica

Table[k = 0; While[Length@ # == 0 &@ Set[f, Select[Rest@ Subsets@ Range@ k, IntegerQ@ Sqrt[n (Times @@ # &[n + #])] &]], k++]; If[IntegerQ@ Sqrt@ n, k = {n}, k = n + Prepend[First@ f, 0]]; Times @@ k, {n, 22}] (* Michael De Vlieger, Oct 26 2016 *)

Formula

a(n) = Product_{k=1..A066400(n)} A245499(n,k), product of n-th row in A245499.

a(n) = A066401(n)^2.