A177321 - OEIS

%I #13 May 16 2020 01:34:50

%S 1,2,416,664958,1792874048,6232521421502,25328979140590460,

%T 114573118435555703030,560523113474283819256640,

%U 2911820015993491302722966990,15861703283168731825003935183416,89796737967084981726163781067177194,524830705066715697873367329722967841532

%N Number of permutations of n copies of 1..9 with all adjacent differences <= 1 in absolute value.

%H Andrew Howroyd, <a href="/A177321/b177321.txt">Table of n, a(n) for n = 0..100</a>

%Y Row n=9 of A331562.

%K nonn

%O 0,2

%A _R. H. Hardin_, May 06 2010

%E a(0)=1 prepended by _Alois P. Heinz_, Jan 20 2020

%E Terms a(6) and beyond from _Andrew Howroyd_, May 15 2020