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A120109
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Row sums of number triangle A120108.
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3
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1, 3, 10, 21, 106, 107, 750, 1501, 4504, 4505, 49556, 49557, 644242, 644243, 644244, 1288489, 21904314, 21904315, 416181986, 416181987, 416181988, 416181989, 9572185748, 9572185749, 47860928746, 47860928747, 143582786242
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OFFSET
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0,2
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COMMENTS
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LINKS
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FORMULA
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a(n) = Sum_{k=0..n} lcm(1,...,n+1)/lcm(1,...,k+1).
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MATHEMATICA
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A120108[n_, k_]:= LCM@@Range[n+1]/(LCM@@Range[k+1]);
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PROG
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(GAP) List([0..30], n->Sum([0..n], k->Lcm(List([1..n+1], i->i))/Lcm(List([1..k+1], i->i)))); # Muniru A Asiru, Mar 03 2019
(PARI) a(n) = lcm([1..n+1])*sum(k=0, n, 1/lcm([1..k+1])); \\ Michel Marcus, Mar 04 2019
(Magma)
A120108:= func< n, k | Lcm([1..n+1])/Lcm([1..k+1]) >;
(SageMath)
def f(n): return lcm(range(1, n+2))
return sum(f(n)//f(k) for k in range(n+1))
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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