[math-fun] A060900 formula

A060900 is the number of unrestricted walks with n edges starting at the origin on the 3/8 square lattice. There is a recursive formula there, though I don't remember putting it there, I could have. Given the nature of the sequence and the number of matching elements, I'm sure the formula is correct, but I admit inability to prove it. However, I have been told the formula is conjectural, and if there is not a proof, it should be marked as such. It is just seems aggravating that I can't come up with one. Anyway, thought the seqfans might want to take a look at it, I know my betters are out there. Similarly, can we come up with a formula for A060897 or A060898? Can we confirm the formula for A060898?