A240804 a(n) = -2 + product of first n odd primes.
1, 13, 103, 1153, 15013, 255253, 4849843, 111546433, 3234846613, 100280245063, 3710369067403, 152125131763603, 6541380665835013, 307444891294245703, 16294579238595022363, 961380175077106319533, 58644190679703485491633, 3929160775540133527939543, 278970415063349480483707693
Offset: 1
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.
Programs
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Magma
[-2+&*[NthPrime(i+1): i in [1..n]]: n in [1..20]]; // Vincenzo Librandi, Apr 15 2014
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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 *)
Formula
a(n) = A070826(n+1)-2. - R. J. Mathar, May 03 2017