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 A210286 Number of 2 X 2 matrices with all elements in {0,1,...,n} and determinant = trace. 3
 1, 3, 10, 18, 28, 42, 56, 74, 96, 118, 140, 170, 200, 234, 272, 302, 336, 386, 432, 482, 536, 578, 624, 690, 752, 810, 876, 938, 1000, 1082, 1156, 1234, 1328, 1402, 1476, 1558, 1632, 1730, 1840, 1926, 2008, 2122, 2228, 2338, 2464, 2554 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS See A210000 for a guide to related sequences. LINKS Chai Wah Wu, Table of n, a(n) for n = 0..10000 MATHEMATICA a = 0; b = n; z1 = 45; t[n_] := t[n] = Flatten[Table[w + z - w*z + x*y, {w, a, b}, {x, a, b}, {y, a, b}, {z, a, b}]] c[n_, k_] := c[n, k] = Count[t[n], k] Table[c[n, 0], {n, 0, z1}]    (* A210286 *) CROSSREFS Cf. A210000. Sequence in context: A031063 A051938 A171834 * A275988 A177955 A298976 Adjacent sequences:  A210283 A210284 A210285 * A210287 A210288 A210289 KEYWORD nonn AUTHOR Clark Kimberling, Mar 19 2012 STATUS approved

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Last modified December 6 08:53 EST 2019. Contains 329788 sequences. (Running on oeis4.)