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A078636
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a(n) = rad(n*(n+1)).
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3
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2, 6, 6, 10, 30, 42, 14, 6, 30, 110, 66, 78, 182, 210, 30, 34, 102, 114, 190, 210, 462, 506, 138, 30, 130, 78, 42, 406, 870, 930, 62, 66, 1122, 1190, 210, 222, 1406, 1482, 390, 410, 1722, 1806, 946, 330, 690, 2162, 282, 42, 70, 510, 1326, 1378, 318, 330, 770, 798
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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a(n) = rad(n*(n+1)) = rad(n)*rad(n+1), mu(a(n)) = mu(rad(n*(n+1))) = mu(rad(n))*mu(rad(n+1)), where rad=A007947 and mu=A008683. - Reinhard Zumkeller, Aug 05 2003
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EXAMPLE
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a(3)=6 as rad(3*4)=rad(12)=rad(2*2*3)=2*3=6.
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MAPLE
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end proc:
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MATHEMATICA
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rad[n_] := Times @@ FactorInteger[n][[All, 1]];
a[n_] := rad[n(n+1)];
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PROG
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(PARI) rad(n)=local(p, i); p=factor(n)[, 1]; prod(i=1, length(p), p[i])
for (k=1, 100, print1(rad(k*(k+1))", "))
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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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