%I #10 Oct 15 2019 01:34:56

%S 1,1,18,18,252,252,3168,3168,37512,37512,427608,427608,4748472,

%T 4748472,51736248,51736248,555626232,555626232,5900636088,5900636088,

%U 62105724792,62105724792,648951523128,648951523128,6740563708152

%N Number of palindromes of length n and containing the digit 1 (or any other fixed nonzero digit).

%F Empirical g.f.: -x*(x-1)*(x+1)^2 / ((3*x-1)*(3*x+1)*(10*x^2-1)). [_Colin Barker_, Feb 15 2013]

%e For length 3 we find 18 numbers: 101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 212, 313, 414, 515, 616, 717, 818, 919.

%Y Cf. A050683, A050720.

%K nonn,base

%O 1,3

%A _Patrick De Geest_, Aug 15 1999

%E More terms from Michael Lugo (mlugo(AT)thelabelguy.com), Dec 22 1999