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A211055 Number of 2 X 2 matrices having all terms in {1,...,n} and determinant n+1. 2
0, 1, 4, 9, 20, 23, 51, 55, 88, 79, 181, 121, 214, 222, 323, 227, 484, 299, 605, 488, 604, 457, 1102, 623, 902, 876, 1269, 769, 1754, 893, 1728, 1370, 1634, 1436, 2811, 1303, 2100, 1964, 3184, 1637, 3622, 1823, 3403, 3171, 3138 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
COMMENTS
For a guide to related sequences, see A210000.
LINKS
MATHEMATICA
a = 1; b = n; z1 = 45;
t[n_] := t[n] = Flatten[Table[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, n + 1], {n, 1, z1}] (* A211055 *)
CROSSREFS
Sequence in context: A241351 A023377 A187408 * A336025 A308482 A136769
KEYWORD
nonn
AUTHOR
Clark Kimberling, Mar 31 2012
STATUS
approved

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Last modified February 23 08:25 EST 2024. Contains 370269 sequences. (Running on oeis4.)