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2, 13, 90, 629, 4402, 30813, 215690, 1509829, 10568802, 73981613, 517871290, 3625099029, 25375693202, 177629852413, 1243408966890, 8703862768229, 60927039377602, 426489275643213, 2985424929502490, 20897974506517429
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,1
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LINKS
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FORMULA
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a(n) = 7*a(n-1)-1.
a(n) = 8*a(n-1)-7*a(n-2).
G.f.: (2-3*x)/((1-x)*(1-7*x)).
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MATHEMATICA
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(11*7^Range[0, 20]+1)/6 (* or *) LinearRecurrence[{8, -7}, {2, 13}, 20] (* Harvey P. Dale, May 05 2019 *)
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PROG
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(Magma) [(11*7^n+1)/6: n in [0..30]];
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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