A210286 - OEIS

A210286

Number of 2 X 2 matrices with all elements in {0,1,...,n} and determinant = trace.

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

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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 A372608

Adjacent sequences: A210283 A210284 A210285 * A210287 A210288 A210289

KEYWORD

nonn

AUTHOR

Clark Kimberling, Mar 19 2012

STATUS

approved