Numbers k such that (k^2 - 7)/2 is a square.

Terms

a(0) =3a(1) =5a(2) =13a(3) =27a(4) =75a(5) =157a(6) =437a(7) =915a(8) =2547a(9) =5333a(10) =14845a(11) =31083a(12) =86523a(13) =181165a(14) =504293a(15) =1055907a(16) =2939235a(17) =6154277a(18) =17131117a(19) =35869755a(20) =99847467a(21) =209064253a(22) =581953685a(23) =1218515763a(24) =3391874643a(25) =7102030325a(26) =19769294173a(27) =41393666187a(28) =115223890395a(29) =241259966797