A119424 - OEIS

%I #3 Mar 30 2012 18:40:37

%S 3,18,84,373,1410

%N Length of primes formed by the initial decimal digits of the base e expansion of Pi.

%e a(1) = 3 because the first 3 digits of the base e expansion of Pi are 10.1 [meaning pi ~ 1*(e^1) + 0*(e^0) + 1*(e^-1)] and 101 (base 10) is prime.

%e a(2) = 18 because the first 18 digits of the base e expansion of Pi are 1, 0, 1010020200021111 which (base 10) is prime.

%e a(3) = 84 because there are 84 digits in 101010020200021111200201011200010102020001110120200101200020011011201012100100021001 which is prime.

%Y Cf. A000040, A005042, A050948.

%K base,nonn

%O 1,1

%A _Jonathan Vos Post_, Jul 26 2006