A117858 Number of palindromes of length n (in base 6).

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

Links

Table of n, a(n) for n=1..30.

Index entries for linear recurrences with constant coefficients, signature (0,6).

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 A106830

Adjacent sequences: A117855 A117856 A117857 * A117859 A117860 A117861

Keyword

nonn,base,easy

Author

Martin Renner, May 02 2006

Extensions

More terms from Colin Barker, Feb 15 2013

Status

approved