Triangle with Euler (secant) numbers, read by rows, T(n, k) for 0 <= k <= n.

Terms

a(0) =1a(1) =-1a(2) =1a(3) =5a(4) =-10a(5) =5a(6) =-61a(7) =183a(8) =-183a(9) =61a(10) =1385a(11) =-5540a(12) =8310a(13) =-5540a(14) =1385a(15) =-50521a(16) =252605a(17) =-505210a(18) =505210a(19) =-252605a(20) =50521a(21) =2702765a(22) =-16216590a(23) =40541475a(24) =-54055300a(25) =40541475a(26) =-16216590a(27) =2702765a(28) =-199360981a(29) =1395526867