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A240804 a(n) = -2 + product of first n odd primes. 2
1, 13, 103, 1153, 15013, 255253, 4849843, 111546433, 3234846613, 100280245063, 3710369067403, 152125131763603, 6541380665835013, 307444891294245703, 16294579238595022363, 961380175077106319533, 58644190679703485491633, 3929160775540133527939543, 278970415063349480483707693 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..200

Des MacHale, Infinitely many proofs that there are infinitely many primes, Math. Gazette, 97 (No. 540, 2013), 495-498.

FORMULA

a(n) = A070826(n+1)-2. - R. J. Mathar, May 03 2017

MATHEMATICA

Table[Product[Prime[k + 1], {k, 1, n}] - 2, {n, 1, 40}] (* Vincenzo Librandi, Apr 15 2014 *)

Rest[FoldList[Times, 1, Prime[Range[2, 20]]]]-2 (* Harvey P. Dale, Mar 17 2015 *)

PROG

(MAGMA) [-2+&*[NthPrime(i+1): i in [1..n]]: n in [1..20]]; // Vincenzo Librandi, Apr 15 2014

CROSSREFS

Cf. A000945, A000946, A005265, A005266, A240803.

Sequence in context: A220734 A268991 A216179 * A100277 A087398 A080440

Adjacent sequences:  A240801 A240802 A240803 * A240805 A240806 A240807

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Apr 14 2014

STATUS

approved

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Last modified June 18 01:16 EDT 2021. Contains 345098 sequences. (Running on oeis4.)