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A051312 Euclid-Mullin sequence (A000945) with initial value a(1)=19 instead of a(1)=2. 3

%I #25 Oct 07 2023 05:25:17

%S 19,2,3,5,571,271,457,397,1123,23,103,42572757267735264511,313,17,

%T 16013177,7951,1259,41,1531,11,83,53,67,7,21397,13,1619,1274209367143,

%U 433,37,491,29,658837,135202080527,163,587,31,2797,35286479

%N Euclid-Mullin sequence (A000945) with initial value a(1)=19 instead of a(1)=2.

%H Tyler Busby, <a href="/A051312/b051312.txt">Table of n, a(n) for n = 1..50</a> (terms 1..42 from Robert Price)

%t a[1]=19; a[n_] := First[ Flatten[ FactorInteger[ 1+Product[ a[ j ], {j, 1, n-1} ] ] ] ]; Array[a, 10]

%o (PARI) spf(n)=factor(n)[1, 1]

%o first(m)=my(v=vector(m)); v[1]=19; for(i=2, m, v[i]=spf(1+prod(j=1, i-1, v[j]))); v; \\ _Anders Hellström_, Aug 31 2015

%Y Cf. A000945, A000946, A005265, A005266.

%K nonn

%O 1,1

%A _Labos Elemer_

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Last modified April 18 04:31 EDT 2024. Contains 371767 sequences. (Running on oeis4.)