A130599 Transformation of sequence 3^k by sandwiching it between 1's.

1, 1, 1, 3, 1, 9, 1, 27, 1, 81, 1, 243, 1, 729, 1, 2187, 1, 6561, 1, 19683, 1, 59049, 1, 177147, 1, 531441, 1, 1594323, 1, 4782969, 1, 14348907, 1, 43046721, 1, 129140163, 1, 387420489, 1, 1162261467, 1, 3486784401, 1, 10460353203, 1, 31381059609, 1, 94143178827

Offset

0,4

Links

Table of n, a(n) for n=0..47.

Index entries for linear recurrences with constant coefficients, signature (0,4,0,-3).

Formula

From Chai Wah Wu, Jan 09 2021: (Start)

a(n) = 4*a(n-2) - 3*a(n-4) for n > 3.

G.f.: (-x^3 - 3*x^2 + x + 1)/(3*x^4 - 4*x^2 + 1). (End)

Crossrefs

Cf. A000244.

Sequence in context: A070894 A090261 A303552 * A157674 A360752 A063467

Adjacent sequences: A130596 A130597 A130598 * A130600 A130601 A130602

Keyword

nonn,less

Author

Paul Curtz, Jun 17 2007

Status

approved