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 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. 2
 1, 8, 89, 1482, 33737, 974860, 34078585, 1397335710, 65753020657, 3493075453208, 206827445591945, 13508998509463890, 965035059918868889, 74859785094041370724, 6267261735949374860857, 563289843479215734940710, 54100963704277853262416833 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 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 LINKS Alois P. Heinz, Table of n, a(n) for n = 1..300 Mikelis Emils Mikelsons, List of expressions for a(5) FORMULA a(n) = Sum_{i=1..n) binomial(n,i)*A140606(i). - Mikelis Emils Mikelsons, Sep 01 2021 EXAMPLE 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. CROSSREFS Cf. A133568, A140606. Sequence in context: A295244 A264072 A303056 * A105718 A045732 A077192 Adjacent sequences:  A131652 A131653 A131654 * A131656 A131657 A131658 KEYWORD nonn AUTHOR Daniel Rainjonneau (d.rainjonneau(AT)wanadoo.fr), Sep 11 2007 EXTENSIONS Definition corrected by Rick L. Shepherd, Sep 16 2007 a(5)-a(17) from Mikelis Emils Mikelsons, Sep 01 2021 STATUS approved

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Last modified August 15 17:39 EDT 2022. Contains 356148 sequences. (Running on oeis4.)