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MATHEMATICA
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Lim=10^4; penlim=Ceiling[Sqrt[2Lim/3]];
PracticalQ[nn_] := Module[{f, p, e, prod=1, ok=True}, If[nn<1 || (nn>1 && OddQ[n]), False, If[nn==1, True, f=FactorInteger[nn]; {p, e} = Transpose[f]; Do[If[p[[i]] > 1+DivisorSigma[1, prod], ok=False; Break[]]; prod=prod*p[[i]]^e[[i]], {i, Length[p]}]; ok]]]; prac= Select[Range[Lim], PracticalQ] ;
seq={}; Do[pen=i(3i-1)/2; peni=prac+pen; AppendTo[seq, peni], {i, 0, penlim}] (* sums of pentagonal and practical numbers *);
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