a(n) = 3^n + 4^n + 5^n.

Terms

a(0) =3a(1) =12a(2) =50a(3) =216a(4) =962a(5) =4392a(6) =20450a(7) =96696a(8) =462722a(9) =2234952a(10) =10873250a(11) =53199576a(12) =261449282a(13) =1289406312a(14) =6376734050a(15) =31605668856a(16) =156925904642a(17) =780248462472