Sums of antidiagonals of number square A110135.

Terms

a(0) =1a(1) =3a(2) =9a(3) =31a(4) =115a(5) =447a(6) =1803a(7) =7499a(8) =32069a(9) =140795a(10) =633981a(11) =2925671a(12) =13826405a(13) =66861107a(14) =330544409a(15) =1669024071a(16) =8598951451a(17) =45160258503a(18) =241540648011