A117860 Number of palindromes of length n (in base 8).

7, 7, 56, 56, 448, 448, 3584, 3584, 28672, 28672, 229376, 229376, 1835008, 1835008, 14680064, 14680064, 117440512, 117440512, 939524096, 939524096, 7516192768, 7516192768, 60129542144, 60129542144, 481036337152, 481036337152, 3848290697216, 3848290697216

Offset

1,1

Links

Table of n, a(n) for n=1..28.

Index entries for linear recurrences with constant coefficients, signature (0,8).

Formula

a(n) = 7*8^floor((n-1)/2).

a(n) = 8*a(n-2). G.f.: 7*x*(1+x)/(1-8*x^2). [Colin Barker, Jun 30 2012]

Mathematica

LinearRecurrence[{0, 8}, {7, 7}, 30] (* Harvey P. Dale, Apr 09 2021 *)

Crossrefs

Cf. A050683.

Sequence in context: A165425 A220079 A153272 * A367456 A360367 A274908

Adjacent sequences: A117857 A117858 A117859 * A117861 A117862 A117863

Keyword

nonn,base,easy

Author

Martin Renner, May 02 2006

Extensions

More terms from Colin Barker, Jun 30 2012

Status

approved