Array read by antidiagonals: poly-Bernoulli numbers B(-k,n).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =1a(6) =1a(7) =4a(8) =4a(9) =1a(10) =1a(11) =8a(12) =14a(13) =8a(14) =1a(15) =1a(16) =16a(17) =46a(18) =46a(19) =16a(20) =1a(21) =1a(22) =32a(23) =146a(24) =230a(25) =146a(26) =32a(27) =1a(28) =1a(29) =64