A201162 - OEIS

%I #9 May 29 2018 18:41:20

%S 1,1,1,1,1,3,4,3,1,1,1,3,6,9,12,15,18,19,18,12,5,1,1,1,3,6,11,16,25,

%T 35,48,62,77,93,111,124,133,134,127,111,85,53,24,7,1

%N Irregular triangle read by rows: number of rank 2 Catalan paths of length n and area k.

%H Brian Drake, <a href="http://dx.doi.org/10.1016/j.disc.2008.11.020">Limits of areas under lattice paths</a>, Discrete Math. 309 (2009), no. 12, 3936-3953. See Section 5.

%e Triangle begins

%e 1

%e 1 1

%e 1 1 3 4 3 1

%e 1 1 3 6 9 12 15 18 19 18 12 5 1

%e 1 1 3 6 11 16 25 35 48 62 77 93 111 124 133 134 127 111 85 53 24 7 1

%e ...

%K nonn,tabf,more

%O 0,6

%A _N. J. A. Sloane_, Nov 27 2011