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Numbers k such that k^2+1 is a triangular number and k^2+2 is a prime number.
5

%I #10 Jan 16 2023 21:41:12

%S 0,3,105,4116315,9721683943673162520781155,

%T 35285058531373239343849920668944097883186271103498415

%N Numbers k such that k^2+1 is a triangular number and k^2+2 is a prime number.

%C a(7) has 191 decimal digits: 222247847...170444715.

%C Corresponding primes and indices of triangular numbers: A226072 and A226073.

%C Subsequence of A106328. - _Max Alekseyev_, Jan 30 2014

%Y Cf. A226069-A226073.

%K nonn

%O 1,2

%A _Alex Ratushnyak_, May 25 2013