Number Wall diagonals

Michael Somos somos at
Sun Jun 18 20:51:09 CEST 2000

Dear seqfans,

Some very interesting sequences arise from diagonals of number tables.
For example, just today I was examining the Number Wall associated with
the coefficients of the expansion of the solution of the equation
(1-2*x)^2*y = (1-3*x)*(1+x*y^2) evaluated at x=0. This sequence goes
1,2,5,14,42,133,443,... and is similar to Catalan Numbers. The diagonal
sequence from the Number Wall is 1,1,1,2,3,7,23,59,... which is a very
nice sequence. Try this with the Catalan numbers first and see what you get.
Shalom, Michael

Michael Somos <somos at>     Cleveland State University            Cleveland, Ohio, USA 44115

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