A133043 Number of segments needed to draw the spiral of equilateral triangles with side lengths which follow the Padovan sequence.

3, 5, 6, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65

Offset

1,1

Links

Table of n, a(n) for n=1..61.

Index entries for linear recurrences with constant coefficients, signature (2,-1).

Formula

a(1)=3: a(2)=5: a(3)=6; for n>3, a(n)=n+4.

Mathematica

LinearRecurrence[{2, -1}, {3, 5, 6, 8, 9}, 70] (* Harvey P. Dale, Dec 21 2018 *)

Prog

(PARI) a(n)=if(n>3, n+4, [3, 5, 6][n]) \\ Charles R Greathouse IV, Oct 27 2011

Crossrefs

Cf. Padovan sequence: A000931.

Sequence in context: A201906 A267158 A161529 * A094058 A288134 A175966

Adjacent sequences: A133040 A133041 A133042 * A133044 A133045 A133046

Keyword

easy,nonn

Author

Omar E. Pol, Nov 04 2007, Nov 05 2007

Status

approved