cp's OEIS Frontend

A226436 Number of permutations of {1..n} with fewer than 3 interior elements having values lying between the values of their neighbors.

%I A226436 #9 Jul 17 2024 18:56:27
%S A226436 1,1,2,6,24,118,658,4078,27724,205134,1641534,14132390,130299584,
%T A226436 1281352790,13391026730,148237230942,1733059331604,21341010960286,
%U A226436 276120222880246,3745333514843734,53149568086851784,787599172764342822,12166057777073762082
%N A226436 Number of permutations of {1..n} with fewer than 3 interior elements having values lying between the values of their neighbors.
%H A226436 Alois P. Heinz, <a href="/A226436/b226436.txt">Table of n, a(n) for n = 0..483</a> (terms n = 1..210 from R. H. Hardin)
%e A226436 Some solutions for n=9
%e A226436 ..6....4....3....9....7....7....9....5....8....8....1....8....8....7....6....2
%e A226436 ..1....2....2....2....3....4....3....3....1....4....4....3....4....1....4....1
%e A226436 ..3....8....8....1....2....8....4....9....9....3....3....9....2....2....8....7
%e A226436 ..9....3....7....6....8....3....2....1....4....7....5....5....9....6....5....9
%e A226436 ..5....7....5....5....5....5....5....8....6....6....2....7....1....3....9....3
%e A226436 ..2....9....6....3....1....9....7....2....7....2....8....4....5....5....2....6
%e A226436 ..8....1....4....7....6....1....6....7....3....9....9....6....3....8....3....4
%e A226436 ..4....5....9....4....4....6....1....4....5....1....7....2....6....4....1....5
%e A226436 ..7....6....1....8....9....2....8....6....2....5....6....1....7....9....7....8
%Y A226436 Column 3 of A226441.
%K A226436 nonn
%O A226436 0,3
%A A226436 _R. H. Hardin_, Jun 06 2013
%E A226436 a(0)=1 prepended by _Alois P. Heinz_, Jul 17 2024