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A018906
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Define the Shallit sequence S(a_0,a_1) by a_{n+2} is the least integer > a_{n+1}^2/a_n for n >= 0. This is S(2,6).
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2
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2, 6, 19, 61, 196, 630, 2026, 6516, 20957, 67403, 216786, 697242, 2242518, 7212542, 23197479, 74609345, 239963764, 771788146, 2482278709, 7983677414, 25677658524, 82586271099, 265619708576, 854304579262, 2747673800490, 8837259564290, 28423008798464
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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) = [ a(n-1)^2/a(n-2)+1 ].
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MAPLE
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a:= proc(n) option remember; `if`(n<2, [2, 6][n+1],
1 +floor(a(n-1)^2/a(n-2)))
end:
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MATHEMATICA
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a[0]=2; a[1]=6; a[n_] := a[n] = Floor[a[n-1]^2/a[n-2]+1]; Table[a[n], {n, 0, 40}] (* Jean-François Alcover, Mar 30 2015 *)
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PROG
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(PARI) a1n=concat([ 2, 6 ], vector(28)); a(n)=a1n[ n+1 ]; for(n=2, 29, a1n[ n+1 ]=1+floor(a(n-1)^2/a(n-2)))
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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