Eulerian numbers (Euler's triangle: column k=2 of A008292, column k=1 of A173018).

Terms

a(0) =0a(1) =0a(2) =1a(3) =4a(4) =11a(5) =26a(6) =57a(7) =120a(8) =247a(9) =502a(10) =1013a(11) =2036a(12) =4083a(13) =8178a(14) =16369a(15) =32752a(16) =65519a(17) =131054a(18) =262125a(19) =524268a(20) =1048555a(21) =2097130a(22) =4194281a(23) =8388584a(24) =16777191a(25) =33554406a(26) =67108837a(27) =134217700a(28) =268435427a(29) =536870882