a(n) = 4*a(n-1) + 5*a(n-2) for n > 1, with a(0) = 2 and a(1) = 4.

A087404

a(n) = 4*a(n-1) + 5*a(n-2) for n > 1, with a(0) = 2 and a(1) = 4.

Terms

    a(0) =2a(1) =4a(2) =26a(3) =124a(4) =626a(5) =3124a(6) =15626a(7) =78124a(8) =390626a(9) =1953124a(10) =9765626a(11) =48828124a(12) =244140626a(13) =1220703124a(14) =6103515626a(15) =30517578124a(16) =152587890626a(17) =762939453124

External references