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A117858
Number of palindromes of length n (in base 6).
0
5, 5, 30, 30, 180, 180, 1080, 1080, 6480, 6480, 38880, 38880, 233280, 233280, 1399680, 1399680, 8398080, 8398080, 50388480, 50388480, 302330880, 302330880, 1813985280, 1813985280, 10883911680, 10883911680, 65303470080, 65303470080, 391820820480, 391820820480
OFFSET
1,1
FORMULA
a(n) = 5*6^floor((n-1)/2).
a(n) = 6*a(n-2). G.f. -5*x*(x+1)/(6*x^2-1). [Colin Barker, Feb 15 2013]
MATHEMATICA
LinearRecurrence[{0, 6}, {5, 5}, 30] (* Harvey P. Dale, Dec 09 2023 *)
CROSSREFS
Cf. A050683.
Sequence in context: A020551 A153271 A261569 * A365824 A014434 A375989
KEYWORD
nonn,base,easy
AUTHOR
Martin Renner, May 02 2006
EXTENSIONS
More terms from Colin Barker, Feb 15 2013
STATUS
approved