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A120173
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a(n) = 4 + floor((3 + Sum_{j=1..n-1} a(j))/5).
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1
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4, 5, 6, 7, 9, 10, 12, 15, 18, 21, 26, 31, 37, 44, 53, 64, 77, 92, 110, 132, 159, 191, 229, 275, 330, 396, 475, 570, 684, 821, 985, 1182, 1418, 1702, 2042, 2451, 2941, 3529, 4235, 5082
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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)/5);
end for;
return t;
end function;
g:= func< n, a, b | f(n+1, a, b)-f(n, a, b) >;
(SageMath)
@CachedFunction
def f(n, p, q): return p + (q +sum(f(k, p, q) for k in range(1, n)))//5
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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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