A014610 Tetranacci numbers arising in connection with current algebras sp(2)_n.

3, 5, 10, 19, 37, 71, 137, 264, 509, 981, 1891, 3645, 7026, 13543, 26105, 50319, 96993, 186960, 360377, 694649, 1338979, 2580965, 4974970, 9589563, 18484477, 35629975, 68678985, 132383000, 255176437