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Search: id:A091061
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| A091061 |
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Number of n X n matrices over symbol set {1,2,3,4} equivalent under any permutation of row, columns or the symbol set. |
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+0
3
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| 1, 1, 9, 408, 332034, 3327329224, 382430372929443, 521184164586987473279, 8728898357751671813141271503, 1850296785573740600565249566845514268, 5085095493754879591102840109774321148107411672
(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+...=4} (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: A058850 A151632 A035024 this_sequence A024123 A081481 A160376
Adjacent sequences: A091058 A091059 A091060 this_sequence A091062 A091063 A091064
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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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