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A120154
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a(n) = 9 + floor( Sum_{j=1..n-1} a(j)/3 ).
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1
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9, 12, 16, 21, 28, 37, 50, 66, 88, 118, 157, 209, 279, 372, 496, 661, 882, 1176, 1568, 2090, 2787, 3716, 4955, 6606, 8808, 11744, 15659, 20879, 27838, 37118, 49490, 65987, 87983, 117310, 156414, 208552, 278069, 370759, 494345, 659127
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OFFSET
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1,1
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LINKS
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MATHEMATICA
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PROG
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(Magma)
function f(n, a, b)
t:=0;
for k in [1..n-1] do
t+:= a+Floor((b+t)/3);
end for;
return t;
end function;
g:= func< n, a, b | f(n+1, a, b)-f(n, a, b) >;
(SageMath)
@CachedFunction
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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