A383202 - OEIS

A383202

Number of positive integers with n digits in which adjacent digits differ by at most 7.

9, 86, 813, 7693, 72786, 688661, 6515721, 61648078, 583279341, 5518660133, 52214449434, 494023669525, 4674173312097, 44224391459894, 418426247682381, 3958913146568317, 37457003208767394, 354397037125653845, 3353104871295311673, 31725187008033469918

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..20.

Index entries for linear recurrences with constant coefficients, signature (9,5,-6).

FORMULA

G.f.: -x*(6*x^2-5*x-9)/(6*x^3-5*x^2-9*x+1). - Alois P. Heinz, Apr 26 2025

MATHEMATICA

Rest[CoefficientList[Series[-x*(6*x^2-5*x-9)/(6*x^3-5*x^2-9*x+1), {x, 0, 20}], x]] (* or *) LinearRecurrence[{9, 5, -6}, {9, 86, 813}, 20] (* James C. McMahon, May 07 2025 *)

CROSSREFS

Cf. A235163, A383197, A383198, A383199, A383200, A383201.

Sequence in context: A029711 A204465 A276242 * A015581 A152261 A028339

Adjacent sequences: A383199 A383200 A383201 * A383203 A383204 A383205

KEYWORD

nonn,base,easy

AUTHOR

Edwin Hermann, Apr 19 2025

EXTENSIONS

a(11)-a(20) from Alois P. Heinz, Apr 26 2025

STATUS

approved