A383071 Number of n-digit positive integers where all pairs of consecutive digits have a difference of at least 3.

9, 49, 282, 1597, 9110, 51800, 294962, 1678509, 9554447, 54379100, 309516061, 1761665068, 10026939872, 57070448658, 324829258129, 1848836718933, 10523062986178, 59894327810129, 340901772402794, 1940317523613740, 11043744749517210, 62857906319753189

Offset: 1

Author

Edwin Hermann, Apr 15 2025

Keywords

• nonn
• base
• easy

Links

• Index entries for linear recurrences with constant coefficients, signature (3,15,2,-1).

Crossrefs

Cf. A052268, A100062, A383070, A383072.

Programs

Mathematica

LinearRecurrence[{3,15,2,-1},{9, 49, 282, 1597},22] (* or *) Rest[CoefficientList[Series[x*(2*x^3-22*x-9)/(-x^4+2*x^3+15*x^2+3*x-1),{x,0,22}] ,x]] (* James C. McMahon, Apr 15 2025 *)

Formula

G.f.: x*(2*x^3-22*x-9)/(-x^4+2*x^3+15*x^2+3*x-1). - Alois P. Heinz, Apr 15 2025

Extensions

More terms from Alois P. Heinz, Apr 15 2025