%I #30 Sep 06 2024 16:53:17

%S 3,7,16,36,78,144,222,324,438,668,900,1148,1518,1764,2022,2492,3128,

%T 3600,4088,4758,5184,5768,6558,7388,8634,9798,10404,11022,11664,12318,

%U 14352,16638,17948,19044,20712,22500,23708,25592,27222,28892

%N a(n) = prime(n)*prime(n-1) + 1.

%C This sequence assumes prime(0) = 1.

%H Harvey P. Dale, <a href="/A023523/b023523.txt">Table of n, a(n) for n = 1..1000</a>

%t f[n_]:=Prime[n]*Prime[n+1]+1; Table[f[n],{n,5!}] (* _Vladimir Joseph Stephan Orlovsky_, Feb 10 2010 *)

%t Join[{3},Times@@@Partition[Prime[Range[40]],2,1]+1] (* _Harvey P. Dale_, Oct 02 2012 *)

%o (Magma) [&+[(NthPrime(n-1)*NthPrime(n)+1)]: n in [1..1000]]; // _Vincenzo Librandi_, Dec 23 2010

%o (Haskell)

%o a023523 n = a023523_list !! (n-1)

%o a023523_list = map (+ 1) $ zipWith (*) a000040_list a008578_list

%o -- _Reinhard Zumkeller_, Oct 09 2012

%Y Cf. A000040, A008578.

%Y From a(2) = 7 onward, column 5 of A286623, column 3 of A328464.

%K nonn

%O 1,1

%A _Clark Kimberling_