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a(n) = (p(1)*...*p(n)) + (p(n+1)*...*p(2n)) where p(n) is the n-th prime.
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%I #15 Apr 13 2024 22:20:09

%S 2,5,41,1031,46399,2803043,247140857,25627356863,3359824134707,

%T 525738142728791,86239154183764823,16043263583368582931,

%U 3203015861712721419161,765364544804215147351277,196164712685969109811322179,51407675872783850510756055649

%N a(n) = (p(1)*...*p(n)) + (p(n+1)*...*p(2n)) where p(n) is the n-th prime.

%F a(n) = A002110(n) + A107712(n).

%e a(5) = 2803043 because 2*3*5*7*11 + 13*17*19*23*29 = 2803043.

%p a:= n-> add(mul(ithprime(i+j), i=1..n), j=[0, n]):

%p seq(a(n), n=0..20); # _Alois P. Heinz_, Apr 13 2024

%Y Cf. A000040, A002110, A107712.

%K easy,nonn

%O 0,1

%A _Jason Earls_, May 12 2004