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 A275234 Number of distinct positive solutions to the system of n Diophantine equations: x_1+y_1=x_2*y_2, x_2+y_2=x_3*y_3, ..., x_n+y_n=x_1*y_1. 1
 1, 2, 2, 3, 3, 5, 4, 7, 7, 12, 12, 21, 22, 37, 47, 72, 93, 145, 198, 303, 427, 637, 917, 1383, 2008 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS In any solution, interchanging x_i and y_i for any i yields a new solution. So does a circular permutation of the solution. Two solutions are counted as distinct if one cannot be gotten from the other by these transformations. LINKS Christopher Briggs, Python script for generating nth term Christopher Briggs, Y. Hirano, H. Tsutsui, Positive Solutions to Some Systems of Diophantine Equations, Journal of Integer Sequences, 2016 Vol 19 #16.8.4. EXAMPLE For n = 1, the only positive solution to x+y = xy is x = y = 2. For n = 2, the only distinct (see comments) positive solutions to x_1+y_2 = x_2*y_2, x_2+y_2 = x_1+y_1 are (x_1,y_1,x_2,y_2) = (2,2,2,2) or (1,5,2,3). CROSSREFS Sequence in context: A035574 A036819 A114328 * A097366 A139807 A308465 Adjacent sequences:  A275231 A275232 A275233 * A275235 A275236 A275237 KEYWORD nonn,more AUTHOR Christopher Briggs, Jul 20 2016 STATUS approved

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Last modified September 28 13:24 EDT 2020. Contains 337393 sequences. (Running on oeis4.)