A132278 - OEIS

%I #2 Mar 30 2012 17:36:15

%S 1,1,2,3,5,7,10,13,17,21,26,31,37,43,49,56,64,72,81,90,100,110,121,

%T 132,144,156,169,182,196,210,225,240,256,272,289,306,324,342,361,380,

%U 400,420,441,462,484,506,529,552,575,599,624,649,675,701,728,755,783

%N Number of distinct terms in rows 1 through n of the triangle of the Narayana numbers (A001263).

%e a(6)=7 because there are 7 distinct terms in the rows 1 through 6 of the triangle of the Narayana numbers: 1; 1,1; 1,3,1; 1,6,6,1; 1,10,20,10,1; 1,15,50,50,15,1.

%p seq(nops(`union`(seq({seq(binomial(n,k)*binomial(n,k-1)/n,k=1..n)},n=1..m))), m=1..57);

%Y Cf. A001263.

%K nonn

%O 1,3

%A _Emeric Deutsch_, Aug 26 2007