%I A001881 M5116 N2217
%S A001881 1,21,378,6930,135135,2837835,64324260,1571349780,41247931725,1159525191825,
%T A001881 34785755754750,1109981842719750,37554385678684875,1343291487737574375
%N A001881 Coefficients of Bessel polynomials y_n (x).
%D A001881 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A001881 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 
               (includes this sequence).
%D A001881 J. Riordan, Combinatorial Identities, Wiley, 1968, p. 77.
%H A001881 <a href="Sindx_Be.html#Bessel">Index entries for sequences related to 
               Bessel functions or polynomials</a>
%F A001881 (2n-5)!/ [5!*(n-5)!*2^(n-5) ].
%F A001881 a(n)= binomial(n-3,2)*(2*n-5)!!/5!!, n>=5, with (2*n-5)!! = A001147(n-2).
%Y A001881 See A001518.
%Y A001881 (1/4) the coefficient of x^2 of polynomials in A098503.
%Y A001881 Column 5 of triangle A001497.
%Y A001881 Third column (m=2) of Laguerre-Sonin a=1/2 triangle A130757.
%Y A001881 Sequence in context: A036904 A134494 A004370 this_sequence A108740 A094172 
               A145613
%Y A001881 Adjacent sequences: A001878 A001879 A001880 this_sequence A001882 A001883 
               A001884
%K A001881 nonn,easy
%O A001881 5,2
%A A001881 N. J. A. Sloane (njas(AT)research.att.com), Simon Plouffe (simon.plouffe(AT)gmail.com)