Diagonal sums of Losanitsch's triangle (A088518?)

[Christian G. Bower]

------ Original Message ------
From: "Alonso Del Arte" <alonso.delarte at gmail.com>
To: seqfan at ext.jussieu.fr
Subject: Diagonal sums of Losanitsch's triangle (A088518?)

> As you all probably already know, the diagonal sums of Pascal's
> triangle are the Fibonacci numbers.
> 
> What about the diagonal sums of Losanitsch's triangle (A034851)? I
> added up about a dozen diagonals and came up with 1, 1, 2, 2, 4, 5, 9,
> 12, 21, 29, 50.

After 21 it goes: 30, 51, 76, ...

You'll find it at A001224, A068928 and A102526.

> An OEIS search for this brings up one result, A088518,
> Symmetric secondary structures of RNA molecules with n nucleotides.
> One of the formulas given involves Fibonacci numbers, Catalan numbers
> and flooring n/2.
> 
> Can someone verify if indeed the diagonal sums of Losanitsch's
> triangle give this biochemically related sequence?
> 
> Alonso
>