login
Decimal expansion of 17*(5 - 3*A136141)/100.
2

%I #9 Aug 20 2024 01:53:14

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

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

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

%N Decimal expansion of 17*(5 - 3*A136141)/100.

%C Lower bound of Product_{p prime} (1 - (1/(p*(p - 1)))*p^2/(p^2 + 1)) = A374831.

%H Rafael Jakimczuk, <a href="https://www.researchgate.net/publication/382207808_Numbers_of_the_form_p-1_where_p_is_prime">Numbers of the form p-1 where p is prime</a>, July 2024. See pp. 23-24.

%F Equals (3/5)*(17/20)*(1 - (A136141 - (1/2 + 1/6))) (see Jakimczuk).

%F Equals (125/153)*A374829.

%e 0.45569009878460448478917259547346937823444191859757511536...

%o (PARI) 17*(5 - 3*sumeulerrat(1/(p*(p-1))))/100 \\ _Amiram Eldar_, Aug 20 2024

%Y Cf. A136141, A374829, A374831.

%K nonn,cons

%O 0,1

%A _Stefano Spezia_, Jul 21 2024