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 A112986 Crossing number of K_{4,n} on the real projective plane. 1
 0, 0, 0, 3, 5, 7, 18, 22, 26, 45, 51, 57, 84, 92, 100, 135, 145, 155, 198, 210, 222, 273, 287, 301, 360, 376, 392, 459, 477, 495, 570, 590, 610, 693, 715, 737, 828, 852, 876, 975, 1001, 1027, 1134, 1162, 1190, 1305, 1335, 1365, 1488, 1520, 1552, 1683, 1717, 1751, 1890 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 LINKS P. T. Ho, The crossing number of K_{4,n} on the real projective plane, Discr. Math., 304 (2005), pp. 23-33. Index entries for linear recurrences with constant coefficients, signature (1,0,2,-2,0,-1,1). FORMULA a(n) = floor(n/3)*(2*n-3(1+floor(n/3))). G.f.: -x^3*(5*x^3+2*x^2+2*x+3) / ((x-1)^3*(x^2+x+1)^2). - Colin Barker, Mar 06 2014 CROSSREFS Cf. A008724. Sequence in context: A247164 A064080 A184875 * A052333 A074106 A002261 Adjacent sequences:  A112983 A112984 A112985 * A112987 A112988 A112989 KEYWORD nonn,easy AUTHOR N. J. A. Sloane, Dec 24 2005 STATUS approved

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