A341930 - OEIS

%I #6 Mar 24 2021 02:47:26

%S 2,0,6,7,4,3,5,8,9,1,4,2,0,2,3,4,2,2,9,5,1,8,8,4,7,0,7,5,6,6,7,8,9,5,

%T 2,1,1,1,3,0,9,3,9,0,7,9,7,6,6,8,4,9,5,5,5,6,7,6,5,4,8,5,7,6,2,0,0,7,

%U 7,3,8,8,1,5,5,3,7,6,4,6,9,2,3,9,7,1,1,8,5,8,6,3,2,5,5,7,0,0,0,3,9,6,8

%N Decimal expansion of (A249270 + A340469)/2.

%C With this constant r(1) and using the formula r(n+1) = (round(r(n))*(r(n) - round(r(n)) + 1.5) it is possible to obtain the sequence of prime numbers because round(r(n)) = prime(n).

%F r(1) = Sum_{k>=1} (prime(k)-1.5)/Product_{i=1..k-1} prime(i).

%e 2.06743589142023422951884707566789...

%o (PARI) suminf(k=1, (prime(k)-1.5)/prod(i=1, k-1, prime(i))) \\ _Michel Marcus_, Feb 23 2021

%Y Cf. A249270, A340469.

%K nonn,cons

%O 1,1

%A _Davide Rotondo_, Feb 23 2021