A023523 - OEIS

A023523

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

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

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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.

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

Sequence in context: A227682 A099325 A026778 * A065979 A106463 A238441

Adjacent sequences: A023520 A023521 A023522 * A023524 A023525 A023526

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved