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 A173636 Number of positive solutions of equation x(x+n)=y*y. 0
 0, 0, 0, 1, 0, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 4, 2, 1, 2, 1, 1, 4, 1, 1, 4, 2, 1, 3, 1, 1, 4, 1, 3, 4, 1, 4, 2, 1, 1, 4, 4, 1, 4, 1, 1, 7, 1, 1, 7, 2, 2, 4, 1, 1, 3, 4, 4, 4, 1, 1, 4, 1, 1, 7, 4, 4, 4, 1, 1, 4, 4, 1, 7, 1, 1, 7, 1, 4, 4 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,10 COMMENTS The solution x=y=0 is not counted. Same as A115878 except for a(0). - Georg Fischer, Oct 12 2018 LINKS FORMULA a(n) = A176835(n)-1. - R. J. Mathar, Nov 23 2010 EXAMPLE a(9)=2 since x(x+9)=y*y has 2 solutions: x=3, y=6 and x=16, y=20. MATHEMATICA Join[{0}, Table[Length[{ToRules[Reduce[x (x + n) == y^2 && x > 0 && y > 0, {x, y}, Integers]]}], {n, 100}]] CROSSREFS Cf. A067721, A115878. Sequence in context: A326851 A129192 A062540 * A115878 A127125 A256671 Adjacent sequences:  A173633 A173634 A173635 * A173637 A173638 A173639 KEYWORD nonn AUTHOR Carmine Suriano, Nov 23 2010 STATUS approved

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Last modified June 30 19:43 EDT 2022. Contains 354945 sequences. (Running on oeis4.)