A137495 a(n) = A098601(2n) + A098601(2n+1).

2, 3, 4, 7, 13, 23, 40, 70, 123, 216, 379, 665, 1167, 2048, 3594, 6307, 11068, 19423, 34085, 59815, 104968, 184206, 323259, 567280, 995507, 1746993, 3065759, 5380032, 9441298, 16568323, 29075380, 51023735, 89540413, 157132471, 275748264, 483904470, 849193147, 1490230088

Offset: 0

Author

Paul Curtz, Apr 27 2008

Keywords

• nonn
• easy

Links

• Nicolas Ollinger and Jeffrey Shallit, The Repetition Threshold for Rote Sequences, arXiv:2406.17867 [math.CO], 2024.
• Index entries for linear recurrences with constant coefficients, signature (2,-1,1)

Crossrefs

Cf. A005314, A135364, A137584, A137531.

Programs

Mathematica

LinearRecurrence[{2, -1, 1}, {2, 3, 4}, 50] (* Paolo Xausa, Jun 29 2024 *)

PARI

Vec((x-2)/(-1+2*x-x^2+x^3)+O(x^99)) \\ Charles R Greathouse IV, Jul 06 2011

Formula

a(3n) = A135364(2n+1). a(3n+1) = A137584(2n+1). a(3n+2) = A137531(2n+2).

From R. J. Mathar, Jul 06 2011: (Start)

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

a(n) = 2*A005314(n+1) - A005314(n). (End)