Numbers k such that 10*k^2 + 9 is a square.

Terms

a(0) =0a(1) =2a(2) =4a(3) =18a(4) =80a(5) =154a(6) =684a(7) =3038a(8) =5848a(9) =25974a(10) =115364a(11) =222070a(12) =986328a(13) =4380794a(14) =8432812a(15) =37454490a(16) =166354808a(17) =320224786a(18) =1422284292a(19) =6317101910a(20) =12160109056a(21) =54009348606a(22) =239883517772a(23) =461763919342