%I A055504
%S A055504 0,0,0,0,0,15,110,455,1400,3570,7980,16170,30360,53625,90090,145145,
%T A055504 225680,340340,499800,717060,1007760,1390515,1887270,2523675,3329480,
%U A055504 4338950,5591300,7131150,9009000,11281725,14013090,17274285,21144480
%N A055504 n*(n-1)*(n-2)*(n-3)*(n-4)*(2*n-1)/72.
%D A055504 L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 73, Problem 3.
%Y A055504 Sequence in context: A143727 A041426 A074877 this_sequence A060931 A107585 
               A054367
%Y A055504 Adjacent sequences: A055501 A055502 A055503 this_sequence A055505 A055506 
               A055507
%K A055504 nonn
%O A055504 0,6
%A A055504 N. J. A. Sloane (njas(AT)research.att.com), Jul 10 2000