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1, 6, 42, 27, 480, 265, 7070, 3815, 1820, 1449, 107338, 56903, 4636632, 2635061, 993850, 633919, 71014372, 42899857, 8111619802, 4675943415, 1414861448, 819657397, 113827776894, 75106291091, 41292848428
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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LINKS
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FORMULA
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MATHEMATICA
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f[n_]:= If[PrimeQ[n], n, 1];
cf[n_]:= cf[n]= If[n==0, 1, f[n]*cf[n-1]]; (* A034386 *)
T[n_, k_]:= T[n, k]= cf[n]^2/(cf[k]*cf[n-k]);
a[n_]:= a[n]= Sum[T[n, k], {k, n}];
Table[a[n], {n, 30}]
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PROG
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(Magma)
A034386:= func< n | n eq 0 select 1 else LCM(PrimesInInterval(1, n)) >;
(SageMath)
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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EXTENSIONS
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Description simplified, offset corrected by the Assoc. Eds. of the OEIS, Jun 27 2010
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STATUS
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approved
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