a(n) = a(n-1) + 10*a(n-2) for n >= 2, a(0)=1, a(1)=2.

Terms

a(0) =1a(1) =2a(2) =12a(3) =32a(4) =152a(5) =472a(6) =1992a(7) =6712a(8) =26632a(9) =93752a(10) =360072a(11) =1297592a(12) =4898312a(13) =17874232a(14) =66857352a(15) =245599672a(16) =914173192a(17) =3370169912a(18) =12511901832a(19) =46213600952a(20) =171332619272a(21) =633468628792