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A091057
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Number of n X n matrices over symbol set {1,...,n^2} equivalent under any permutation of row, columns or the symbol set.
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7
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1, 1, 9, 777, 18500104, 322286625959257, 7368376339801908226685191, 422262377369187686156418513093399998333, 105882936532098986759153041871810253870024776751177723954
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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LINKS
| C. G. Bower, Explanation of A091057-A091062
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FORMULA
| a(n) = sum {1*s_1+2*s_2+...=n, 1*t_1+2*t_2+...=n, 1*u_1+2*u_2+...=n} (fix A[s_1, s_2, ...;t_1, t_2, ...;u_1, u_2, ...]/(1^s_1*s_1!*2^s_2*s_2!*...*1^t_1*t_1!*2^t_2*t_2!*...*1^u_1*u_1!*2^u_2*u_2!*...)) where fix A[...] = prod {i, j>=1} ( (sum {d|lcm(i, j)} (d*u_d))^(gcd(i, j)*s_i*t_j))
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CROSSREFS
| Cf. A091058-A091062.
Sequence in context: A145183 A124417 A159356 * A168257 A137065 A196981
Adjacent sequences: A091054 A091055 A091056 * A091058 A091059 A091060
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KEYWORD
| nonn
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AUTHOR
| Christian G. Bower (bowerc(AT)usa.net), Dec 17 2003
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EXTENSIONS
| a(7), a(8) from Max Alekseyev (maxale(AT)gmail.com), Feb 09 2010
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