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 A050720 Number of nonzero palindromes of length n containing the digit '0'. 3
 0, 0, 9, 9, 171, 171, 2439, 2439, 30951, 30951, 368559, 368559, 4217031, 4217031, 46953279, 46953279, 512579511, 512579511, 5513215599, 5513215599, 58618940391, 58618940391, 617570463519, 617570463519, 6458134171671 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS FORMULA Empirical g.f.: 9*x^3*(x+1) / ((3*x-1)*(3*x+1)*(10*x^2-1)). [Colin Barker, Feb 15 2013] For n > 1, a(n) = 9*10^(k-1) - 9^k, where k = ceiling(n/2). - Jon E. Schoenfield, Sep 14 2013 EXAMPLE For length 3 we find nine numbers 101, 202, ... 909. MATHEMATICA nzp[n_]:=Module[{k=Ceiling[n/2]}, 9*10^(k-1)-9^k]; Array[nzp, 30] (* Harvey P. Dale, Jun 01 2019 *) CROSSREFS Cf. A050683, A050686. Sequence in context: A092548 A121389 A065242 * A262860 A335026 A171738 Adjacent sequences:  A050717 A050718 A050719 * A050721 A050722 A050723 KEYWORD nonn,base AUTHOR Patrick De Geest, Aug 15 1999 EXTENSIONS More terms from Michael Lugo (mlugo(AT)thelabelguy.com), Dec 22 1999 Corrected by T. D. Noe, Nov 08 2006 STATUS approved

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Last modified September 23 04:54 EDT 2020. Contains 337295 sequences. (Running on oeis4.)