a(n) = a(n-2) + 4*a(n-3) - 4*a(n-5), where a(0) = 1, a(1) = 4, a(2) = 7, a(3) = 12, a(4) = 19, a(5) = 28.

A297554

a(n) = a(n-2) + 4*a(n-3) - 4*a(n-5), where a(0) = 1, a(1) = 4, a(2) = 7, a(3) = 12, a(4) = 19, a(5) = 28.

Terms

    a(0) =1a(1) =4a(2) =7a(3) =12a(4) =19a(5) =28a(6) =51a(7) =76a(8) =115a(9) =204a(10) =307a(11) =460a(12) =819a(13) =1228a(14) =1843a(15) =3276a(16) =4915a(17) =7372a(18) =13107a(19) =19660a(20) =29491a(21) =52428a(22) =78643a(23) =117964a(24) =209715a(25) =314572a(26) =471859a(27) =838860a(28) =1258291a(29) =1887436

External references