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A278377 Number of 2 X 2 matrices with all elements in {0,1,...,n} and determinant n with no elements repeated. 1
0, 0, 0, 4, 8, 16, 40, 36, 72, 60, 128, 92, 232, 144, 260, 284, 332, 252, 564, 324, 680, 568, 696, 492, 1184, 628, 984, 964, 1392, 796, 1920, 924, 1820, 1512, 1752, 1568, 2820, 1380, 2244, 2104, 3340, 1660, 3864, 1900, 3544, 3388, 3300, 2264, 5652, 2632, 4616 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Indranil Ghosh and Chai Wah Wu, Table of n, a(n) for n = 0..3000 (term for n = 0..100 from Indranil Ghosh)

PROG

(Python)

def p(n):

    s=0

    for a in range(0, n+1):

        for b in range(0, n+1):

            for c in range(0, n+1):

                for d in range(0, n+1):

                    if (a!=b  and a!=d and b!=d and c!=a and c!=b and c!=d):

                        if a*d-b*c==n:

                            s+=1

    return s

for i in range(0, 101):

    print str(i)+" "+str(p(i)) \\ Indranil Ghosh, Nov 20, 2016

CROSSREFS

Cf. A210282 (where the matrix elements can be repeated).

Sequence in context: A141069 A306621 A144687 * A065605 A065978 A077447

Adjacent sequences:  A278374 A278375 A278376 * A278378 A278379 A278380

KEYWORD

nonn

AUTHOR

Indranil Ghosh, Nov 20 2016

STATUS

approved

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Last modified October 20 22:00 EDT 2021. Contains 348119 sequences. (Running on oeis4.)