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Search: id:A120494
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| A120494 |
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A vector group determinant sequence in which the next element is made by a sum of the older elements over a vector like 2 X 2 matrix group. |
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+0
1
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| 1, 1, 2, 3, 5, 13, 139, 19136, 366167031, 134078294225149313, 17976988982325707481237962186849833, 323172132870659875927245721269598505772051876540063951439000722587455
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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This sequence type gets very large very fast.
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FORMULA
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s[1] = {{1, 0}, {0, 1}}; s[2] = {{1, 0}, {0, -1}}; s[3] = {{0, 1}, {1, 0}}; s[4] = {{0, 1}, {-1, 0}}; a[0] = {0, 1, 1, 2}; a[1] = {1, 1, 2, 3}; a[n_] := a[n] = {a[n - 1][[2]], a[n - 1][[3]], a[n - 1][[4]], Det[Sum[a[n - 1][[i]]*s[i], {i, 1, 4}]]} a(n)=a[n][[1]]
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MATHEMATICA
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s[1] = {{1, 0}, {0, 1}}; s[2] = {{1, 0}, {0, -1}}; s[3] = {{0, 1}, {1, 0}}; s[4] = {{0, 1}, {-1, 0}}; a[0] = {0, 1, 1, 2}; a[1] = {1, 1, 2, 3}; a[n_] := a[n] = {a[n - 1][[2]], a[n - 1][[3]], a[n - 1][[4]], Det[Sum[a[n - 1][[i]]*s[i], {i, 1, 4}]]} Table[a[n][[1]], {n, 1, 15}]
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CROSSREFS
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Adjacent sequences: A120491 A120492 A120493 this_sequence A120495 A120496 A120497
Sequence in context: A005478 A117740 A041047 this_sequence A164825 A038601 A114747
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KEYWORD
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nonn,uned
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AUTHOR
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Roger Bagula (rlbagulatftn(AT)yahoo.com), Aug 06 2006
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