A224848 - OEIS

%I #16 Jan 16 2023 12:44:06

%S 2,3,14,700,2818

%N Reverse concatenation of the square of first a(n) integers gives a prime.

%C The number corresponding to a(5) = 2818 is a probable prime of 18269 digits. - _Giovanni Resta_, Jul 25 2013

%e a(4) = 700 because reverse concatenation of squares of 1 to 700 gives 490000488601......2516941 which is a 3742-digit prime number.

%Y Cf. A091314.

%K nonn,hard,more,base

%O 1,1

%A _Shyam Sunder Gupta_, Jul 22 2013

%E a(5) from _Giovanni Resta_, Jul 25 2013