A383071 - OEIS

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

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..22.

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

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

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 *)

CROSSREFS

Cf. A052268, A100062, A383070, A383072.

Sequence in context: A012231 A123270 A114040 * A231178 A359204 A090390

Adjacent sequences: A383068 A383069 A383070 * A383072 A383073 A383074

KEYWORD

nonn,base,easy

AUTHOR

Edwin Hermann, Apr 15 2025

EXTENSIONS

More terms from Alois P. Heinz, Apr 15 2025

STATUS

approved