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 A337515 a(n) is the number of essentially different optimal solutions with A336660(n) 1 X 1 cells to R. Kurchan's n-squares puzzle 578. 3
 1, 1, 1, 4, 1, 2, 1, 8, 4, 21, 29 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS Numbers a(n) are a by-product of the exhaustive computation done for A336660. They were communicated privately by Hugo Pfoertner and Hermann Jurksch. For historical background see link section "Pictures of all different solutions for n <= 11". LINKS Rainer Rosenthal, Illustration of a(4). Rainer Rosenthal, Illustration of a(8). Rainer Rosenthal, Data of all different solutions for n <= 11, October 2020. Rainer Rosenthal, Pictures of all different solutions for n <= 11, October 2020. EXAMPLE The square with side length s has lower left corner (x_s,y_s). The a(8) = 8 solutions come in 6 main variations:        x8 y8  x7 y7  x6 y6  x5 y5  x4 y4  x3 y3  x2 y2  x1 y1   V1    0  0   0  2   4  6   5  5   2  7   6  4   1  7   4 10   V2    0  0   2  3   7  0   5  2   7  5   6  1   8  8  10  7   V3+   0  0   3  7   0  3   2  6   5  5   1  7   7  4   3  6     +  .. ..  .. ..  .. ..  .. ..  .. ..  .. ..  .. ..   8  8   V4+   0  0   3  7   0  3   2  6   5  6   1  7   6  9   4 10     +  .. ..  .. ..  .. ..  .. ..  .. ..  .. ..  .. ..   8  8   V5    0  0   4  6   1  3   5  5   2  7   6  4   3 10   2  9   V6    0  0   4  6   5  5   2  4   6  3   3  7   7  2   9  4 The two solutions in V3 are "1-siblings", i.e., they are equal except for (x1,y1). Likewise V4 consists of two 1-siblings. See illustration of a(8) in the link section. CROSSREFS Cf. A336659, A336660, A336782. Sequence in context: A069098 A126241 A019777 * A090885 A008476 A300657 Adjacent sequences:  A337512 A337513 A337514 * A337519 A337521 A337523 KEYWORD nonn,hard,more AUTHOR Rainer Rosenthal, Sep 19 2020 EXTENSIONS a(4) and a(8) corrected by Rainer Rosenthal, Oct 02 2020 STATUS approved

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Last modified October 27 17:15 EDT 2020. Contains 338035 sequences. (Running on oeis4.)