%I #10 Aug 12 2023 10:54:54
%S 1,15,69,255,1097,4765,21237,95873,437537,2012997,9321899,43397633,
%T 202926209,952396005,4484003747,21168581905,100170213121,474981809053,
%U 2256307682541,10735210220803,51148724456627,244007372314919
%N Number of base 15 circular n-digit numbers with adjacent digits differing by 2 or less.
%C [Empirical] a(base,n)=a(base-1,n)+A005191(n+1) for base>=2.int(n/2)+1.
%C See A285280 for confirmation of linear recurrence and code to produce sequence. - _Ray Chandler_, Aug 12 2023.
%H Ray Chandler, <a href="/A124893/b124893.txt">Table of n, a(n) for n = 0..99</a>
%H <a href="/index/Rec#order_15">Index entries for linear recurrences with constant coefficients</a>, signature (15, -78, 130, 176, -682, 44, 1128, -330, -818, 249, 261, -62, -30, 3, 1).
%o (S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-1](($[i]`-$[(i+1)mod N]`>2)+($[(i+1)mod N]`-$[i]`>2))
%Y Cf. Row 15 of A285280.
%K nonn,base
%O 0,2
%A _R. H. Hardin_, Dec 28 2006