A131655 Maximal number of different numbers that can be formed from n numbers using addition, subtraction, multiplication and division, when each number is used no more than once in a given expression.

1, 8, 89, 1482, 33737, 974860, 34078585, 1397335710, 65753020657, 3493075453208, 206827445591945, 13508998509463890, 965035059918868889, 74859785094041370724, 6267261735949374860857, 563289843479215734940710, 54100963704277853262416833

Offset: 1

Author

Daniel Rainjonneau (d.rainjonneau(AT)wanadoo.fr), Sep 11 2007

Keywords

• nonn

Comments

See triangle A133568: Each row gives the least sequence of n positive integers such that a(n) distinct numbers are generated by these operations. - Rick L. Shepherd, Sep 16 2007

Examples

			a(2) = 8 : from two variables x and y we obtain the eight functions x, y, x+y, x*y, x-y, y-x, x/y and y/x.
		

Links

• Alois P. Heinz, Table of n, a(n) for n = 1..300
• Mikelis Emils Mikelsons, List of expressions for a(5)

Crossrefs

Cf. A133568, A140606.

Formula

a(n) = Sum_{i=1..n} binomial(n,i)*A140606(i). - Mikelis Emils Mikelsons, Sep 01 2021

Extensions

Definition corrected by Rick L. Shepherd, Sep 16 2007

a(5)-a(17) from Mikelis Emils Mikelsons, Sep 01 2021