Consider all Pythagorean triples (Y-7,Y,Z); sequence gives Y values.

Terms

a(0) =4a(1) =7a(2) =12a(3) =15a(4) =28a(5) =55a(6) =72a(7) =147a(8) =304a(9) =403a(10) =840a(11) =1755a(12) =2332a(13) =4879a(14) =10212a(15) =13575a(16) =28420a(17) =59503a(18) =79104a(19) =165627a(20) =346792a(21) =461035a(22) =965328a(23) =2021235a(24) =2687092a(25) =5626327a(26) =11780604a(27) =15661503a(28) =32792620a(29) =68662375