Third differences of Catalan numbers A000108.

Terms

a(0) =1a(1) =4a(2) =13a(3) =43a(4) =145a(5) =497a(6) =1727a(7) =6071a(8) =21554a(9) =77180a(10) =278426a(11) =1010990a(12) =3692213a(13) =13553555a(14) =49981875a(15) =185082495a(16) =687923790a(17) =2565602160a(18) =9598056630a(19) =36008860650a(20) =135446603370a(21) =510706730274