Numbers k such that k^3 divides 4^(k^2) + 1.

Terms

a(0) =1a(1) =5a(2) =205a(3) =505a(4) =20705a(5) =40505a(6) =168305a(7) =408545a(8) =1342505a(9) =1660705a(10) =2084645a(11) =4091005a(12) =10201505a(13) =16322105a(14) =16750345a(15) =16998805a(16) =37217545a(17) =49985405a(18) =55042705a(19) =117165905a(20) =135593005a(21) =167731205a(22) =186678805a(23) =210549145a(24) =218301905a(25) =418261705