Arises in enumeration of locally convex functions.

Terms

a(0) =1a(1) =5a(2) =21a(3) =70a(4) =214a(5) =575a(6) =1475a(7) =3500a(8) =7989a(9) =17398a(10) =36719a(11) =74744a(12) =148728a(13) =287857a(14) =545921a(15) =1013777a(16) =1851002a(17) =3319946a(18) =5870355a(19) =10225924a(20) =17591720a(21) =29883756a(22) =50205820a(23) =83417989a(24) =137264233a(25) =223679849a(26) =361319673a(27) =578646237a(28) =919417837a(29) =1449568462