Triangle read by rows: Zig-zag Eulerian number triangle T(n, k).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =3a(7) =1a(8) =1a(9) =7a(10) =7a(11) =1a(12) =1a(13) =14a(14) =31a(15) =14a(16) =1a(17) =1a(18) =26a(19) =109a(20) =109a(21) =26a(22) =1a(23) =1a(24) =46a(25) =334a(26) =623a(27) =334a(28) =46a(29) =1