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 A259088 Number of n-celled polyominoes which are of square type. 3
 1, 0, 1, 1, 6, 7, 25, 80, 255, 795, 2919, 10378, 36590, 130716, 480773, 1774714, 6543633 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 LINKS R. J. Mathar, Corrigendum to "Polynomino enumeration results (Parkin et al, SIAM Fall Meeting 1967)", vixra:1905.0474 T. R. Parkin, L. J. Lander, and D. R. Parkin, Polyomino Enumeration Results, presented at SIAM Fall Meeting, 1967) and accompanying letter from T. J. Lander (annotated scanned copy). See page 21. The 15th entry is not included because their value for A000105(15) was incorrect. FORMULA a(n)+A259087(n) = A000105(n). EXAMPLE a(7) = 25 with 7 free 7-ominoes with a 3x3 hull and 18 with 4x4 hull. a(8) = 80 with 3 free 8-ominoes with a 3x3 hull and 77 with a 4x4 hull. a(9) = 255 with 1 free 9-omino in a 3x3 hull, 181 in a 4x4 hull and 73 in a 5x5 hull. - R. J. Mathar, May 24 2019 CROSSREFS Cf. A259087, A268311, A000105. Sequence in context: A333550 A219916 A135987 * A200179 A054289 A041078 Adjacent sequences:  A259085 A259086 A259087 * A259089 A259090 A259091 KEYWORD nonn,more AUTHOR N. J. A. Sloane, Jun 18 2015 EXTENSIONS Terms for n=15 and 16 added. - R. J. Mathar, May 22 2019 a(17) added. - R. J. Mathar, May 27 2019 STATUS approved

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Last modified April 12 22:36 EDT 2021. Contains 342933 sequences. (Running on oeis4.)