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Column 1 of triangle A107873; a(n) = C( n*(n+1)/2 + n+3, n).
2

%I #5 Feb 27 2013 18:19:54

%S 1,5,28,220,2380,33649,593775,12620256,314457495,8996462475,

%T 290752384208,10477677064400,416579843773639,18114175790089400,

%U 855130180330364620,43553532185070076800,2380434572658017204175

%N Column 1 of triangle A107873; a(n) = C( n*(n+1)/2 + n+3, n).

%t Table[Binomial[(n(n+1))/2+n+3,n],{n,0,20}] (* _Harvey P. Dale_, Feb 27 2013 *)

%o (PARI) a(n)=binomial(n*(n+1)/2+n+3,n)

%Y Cf. A107873, A107874.

%K nonn

%O 0,2

%A _Paul D. Hanna_, Jun 04 2005