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 A289179 Edge count of the n X n white bishop graph. 1
 0, 1, 4, 14, 28, 55, 88, 140, 200, 285, 380, 506, 644, 819, 1008, 1240, 1488, 1785, 2100, 2470, 2860, 3311, 3784, 4324, 4888, 5525, 6188, 6930, 7700, 8555, 9440, 10416, 11424, 12529, 13668, 14910, 16188, 17575, 19000, 20540, 22120, 23821, 25564, 27434, 29348, 31395 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Sequence extended to a(1) using formula. LINKS Eric Weisstein's World of Mathematics, Edge Count Eric Weisstein's World of Mathematics, White Bishop Graph Index entries for linear recurrences with constant coefficients, signature (2, 1, -4, 1, 2, -1). FORMULA a(n) = ((-1 + n)*(-3 + 3*(-1)^n - 2*n + 4*n^2))/12. a(n) = 2*a(n-1)+a(n-2)-4*a(n-3)+a(n-4)+2*a(n-5)-a(n-6). G.f. = x*(x + 2x^2 + 5x^3)/((-1 + x)^4*(1 + x)^2). [Corrected by Georg Fischer, May 19 2019] MATHEMATICA Table[(n - 1) (4 n^2 - 2 n - 3 + 3 (-1)^n)/12, {n, 20}] LinearRecurrence[{2, 1, -4, 1, 2, -1}, {0, 1, 4, 14, 28, 55}, 20] CoefficientList[Series[x(x + 2 x^2+ 5 x^3)/((-1 + x)^4 (1 + x)^2), {x, 0, 20}], x] (* Corrected by Georg Fischer, May 19 2019 *) CROSSREFS Cf. A225972 (black bishop graph edge count). Sequence in context: A304342 A066907 A130439 * A033690 A316213 A296985 Adjacent sequences:  A289176 A289177 A289178 * A289180 A289181 A289182 KEYWORD nonn AUTHOR Eric W. Weisstein, Jun 27 2017 STATUS approved

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Last modified May 26 01:22 EDT 2020. Contains 334613 sequences. (Running on oeis4.)