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Number of palindromes of length n (in base 7).
0

%I #16 Apr 06 2024 05:43:35

%S 6,6,42,42,294,294,2058,2058,14406,14406,100842,100842,705894,705894,

%T 4941258,4941258,34588806,34588806,242121642,242121642,1694851494,

%U 1694851494,11863960458,11863960458,83047723206,83047723206,581334062442,581334062442

%N Number of palindromes of length n (in base 7).

%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (0,7).

%F a(n) = 6*7^floor((n-1)/2).

%F a(n) = 7*a(n-2). G.f.: 6*x*(1+x)/(1-7*x^2). [_Colin Barker_, Jun 30 2012]

%t 6*7^Floor[Range[0,40]/2] (* _Harvey P. Dale_, Mar 23 2012 *)

%Y Cf. A050683.

%K nonn,base,easy

%O 1,1

%A _Martin Renner_, May 02 2006

%E More terms from _Harvey P. Dale_, Mar 23 2012