Number of leg-hypotenuse twin Pythagorean triples < 10^n.

Terms

a(0) =1a(1) =6a(2) =21a(3) =70a(4) =223a(5) =706a(6) =2235a(7) =7070a(8) =22360a(9) =70710a(10) =223606a(11) =707106a(12) =2236067a(13) =7071067a(14) =22360679a(15) =70710677a(16) =223606797a(17) =707106780a(18) =2236067976a(19) =7071067811a(20) =22360679774a(21) =70710678118a(22) =223606797749a(23) =707106781186