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%I A023523 #30 Sep 06 2024 16:53:17
%S A023523 3,7,16,36,78,144,222,324,438,668,900,1148,1518,1764,2022,2492,3128,
%T A023523 3600,4088,4758,5184,5768,6558,7388,8634,9798,10404,11022,11664,12318,
%U A023523 14352,16638,17948,19044,20712,22500,23708,25592,27222,28892
%N A023523 a(n) = prime(n)*prime(n-1) + 1.
%C A023523 This sequence assumes prime(0) = 1.
%H A023523 Harvey P. Dale, <a href="/A023523/b023523.txt">Table of n, a(n) for n = 1..1000</a>
%t A023523 f[n_]:=Prime[n]*Prime[n+1]+1; Table[f[n],{n,5!}] (* _Vladimir Joseph Stephan Orlovsky_, Feb 10 2010 *)
%t A023523 Join[{3},Times@@@Partition[Prime[Range[40]],2,1]+1] (* _Harvey P. Dale_, Oct 02 2012 *)
%o A023523 (Magma) [&+[(NthPrime(n-1)*NthPrime(n)+1)]: n in [1..1000]]; // _Vincenzo Librandi_, Dec 23 2010
%o A023523 (Haskell)
%o A023523 a023523 n = a023523_list !! (n-1)
%o A023523 a023523_list =  map (+ 1) $ zipWith (*) a000040_list a008578_list
%o A023523 -- _Reinhard Zumkeller_, Oct 09 2012
%Y A023523 Cf. A000040, A008578.
%Y A023523 From a(2) = 7 onward, column 5 of A286623, column 3 of A328464.
%K A023523 nonn
%O A023523 1,1
%A A023523 _Clark Kimberling_

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