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%I #19 Jul 05 2019 04:46:20
%S 1,2,15,105,1155,85085,1616615,37182145,1078282205,247357937827,
%T 10141675450907,436092044389001,20496326086283047,1086305282573001491,
%U 64092011671807087969,3909612711980232366109,261944051702675568529303,18598027670889965365580513
%N Smallest deficient number which is the product of n consecutive primes.
%C a(n) is greater than A087234(n) for n = 2, 5, 6, 9, 10, 11, 12, 13, 14, 18, ... By definition, A087234(n) is never greater than a(n).
%e a(5) = 5*7*11*13*17 = 85085.
%t a[n_] := Module[{p = Prime@Range[n]}, While[Times@@(1+1/p) >= 2, p = Rest @ AppendTo[p, NextPrime@p[[-1]]]]; Times@@p]; Array[a, 18, 0] (* _Amiram Eldar_, Jul 04 2019 *)
%o (PARI) a(n)=for(k=1,+oo,p=prod(i=k,k+n-1,prime(i));sigma(p)<2*p && return(p))
%Y Cf. A087234, A073485, A005100.
%K nonn,easy
%O 0,2
%A _Jeppe Stig Nielsen_, Jul 01 2019