Numerators of continued fraction convergents to sqrt(20).

Terms

a(0) =4a(1) =9a(2) =76a(3) =161a(4) =1364a(5) =2889a(6) =24476a(7) =51841a(8) =439204a(9) =930249a(10) =7881196a(11) =16692641a(12) =141422324a(13) =299537289a(14) =2537720636a(15) =5374978561a(16) =45537549124a(17) =96450076809a(18) =817138163596