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

1,2

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)

Formula

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

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

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 *)

Prog

(Haskell)
a245530 = product . a245499_row

Crossrefs

Cf. A006255, A066400, A066401, A245499.

Sequence in context: A067865 A272524 A303899 * A138202 A204106 A049227

Adjacent sequences: A245527 A245528 A245529 * A245531 A245532 A245533

Keyword

nonn

Author

Reinhard Zumkeller, Jul 25 2014

Status

approved