%I A086853
%S A086853 0,0,0,2,10,48,256,1670,12846,112820,1108612,12032154,142852450,1840969784,
%T A086853 25587270600,381460235918,6071318154166,102742200205980,1841978156709676,
%U A086853 34874169034136930,695294184953602602,14560120360421802464,319510983674891800240
%N A086853 Number of permutations of length n with exactly 2 rising or falling successions.
%C A086853 Permutations of 12...n such that exactly 2 of the following occur: 12, 
               23, ..., (n-1)n, 21, 32, ..., n(n-1).
%D A086853 F. N. David, M. G. Kendall and D. E. Barton, Symmetric Function and Allied 
               Tables, Cambridge, 1966, p. 263.
%D A086853 J. Riordan, A recurrence for permutations without rising or falling successions. 
               Ann. Math. Statist. 36 (1965), 708-710.
%F A086853 Coefficient of t^2 in S[n](t) defined in A002464.
%Y A086853 Cf. A002464, A000130, A000349, A001267, A086852, A086854. A diagonal 
               of A001100.
%Y A086853 Sequence in context: A065982 A114693 A121950 this_sequence A036918 A166922 
               A129118
%Y A086853 Adjacent sequences: A086850 A086851 A086852 this_sequence A086854 A086855 
               A086856
%K A086853 nonn
%O A086853 0,4
%A A086853 N. J. A. Sloane (njas(AT)research.att.com), Aug 19 2003