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%I #26 Jul 02 2021 01:56:31
%S 1,5,2071,33421,58061,1977071,7011161,10144571,10189721,166311841,
%T 173618771,215766701,240623221,341359721,341455271,389192441,
%U 490814481,524456461,585387477,888576461,1123952441,1276706071,2005030751,2244832943,2863311531,3104590331,3904529471
%N Numbers k such that 4k - 1 divides 2^k + k^2.
%C Primes: 5, 58061, 341455271,...
%t Select[Range[10^5], Mod[PowerMod[2, #, 4*#-1] + #^2, 4*#-1] == 0 &] (* _Giovanni Resta_, Oct 09 2019 *)
%Y Cf. A001580, A327636, A123047, A327943.
%K nonn
%O 1,2
%A _Juri-Stepan Gerasimov_, Sep 24 2019
%E a(10)-a(27) from _Giovanni Resta_, Oct 09 2019