Row sums of the Riordan matrix (1/sqrt(1-4*x), x/(1-x)) (A187888).

Terms

a(0) =1a(1) =3a(2) =10a(3) =34a(4) =118a(5) =418a(6) =1508a(7) =5524a(8) =20486a(9) =76722a(10) =289580a(11) =1099836a(12) =4198396a(13) =16093236a(14) =61902472a(15) =238805864a(16) =923574598a(17) =3579675026a(18) =13900879132a(19) =54071886764a(20) =210645038548a(21) =821701422716