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Search: id:A091059
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| A091059 |
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Number of n X n matrices over symbol set {1,2} equivalent under any permutation of row, columns or the symbol set. |
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+0
2
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| 1, 1, 5, 18, 173, 2812, 126446, 16821330, 7343033248, 10733521835504, 52867612881649880, 882178115128903807148, 50227997322259477864188380, 9837048598740464300126599181536, 6681839615514161335727724211992609234
(list; graph; listen)
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OFFSET
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0,3
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LINKS
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C. G. Bower, Explanation of A091057-A091062
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FORMULA
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a(n) = sum {1*s_1+2*s_2+...=n, 1*t_1+2*t_2+...=n, 1*u_1+2*u_2=2} (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
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Cf. A091057-A091062.
Sequence in context: A009348 A009365 A140296 this_sequence A139243 A139237 A089082
Adjacent sequences: A091056 A091057 A091058 this_sequence A091060 A091061 A091062
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KEYWORD
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nonn
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AUTHOR
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Christian G. Bower (bowerc(AT)usa.net), Dec 17 2003
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