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 A023523 a(n) = prime(n)*prime(n-1) + 1. 9
 3, 7, 16, 36, 78, 144, 222, 324, 438, 668, 900, 1148, 1518, 1764, 2022, 2492, 3128, 3600, 4088, 4758, 5184, 5768, 6558, 7388, 8634, 9798, 10404, 11022, 11664, 12318, 14352, 16638, 17948, 19044, 20712, 22500, 23708, 25592, 27222, 28892 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS This sequence assumes prime(0) = 1. LINKS Harvey P. Dale, Table of n, a(n) for n = 1..1000 MATHEMATICA f[n_]:=Prime[n]*Prime[n+1]+1; Table[f[n], {n, 5!}] (* Vladimir Joseph Stephan Orlovsky, Feb 10 2010 *) Join[{3}, Times@@@Partition[Prime[Range[40]], 2, 1]+1] (* Harvey P. Dale, Oct 02 2012 *) PROG (MAGMA)[&+[(NthPrime(n-1)*NthPrime(n)+1)]: n in [1..1000]] // Vincenzo Librandi, Dec 23 2010 (Haskell) a023523 n = a023523_list !! (n-1) a023523_list =  map (+ 1) \$ zipWith (*) a000040_list a008578_list -- Reinhard Zumkeller, Oct 09 2012 CROSSREFS Cf. A000040, A008578. Row 5 of A286625, column 5 of A286623 (from a(2) = 7 onward). Sequence in context: A227682 A099325 A026778 * A065979 A106463 A238441 Adjacent sequences:  A023520 A023521 A023522 * A023524 A023525 A023526 KEYWORD nonn AUTHOR STATUS approved

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Last modified April 23 22:17 EDT 2019. Contains 322388 sequences. (Running on oeis4.)