A383079 Number of n-digit positive integers where all pairs of consecutive digits have a difference of at least 7.

9, 9, 22, 48, 109, 244, 549, 1233, 2771, 6226, 13990, 31435, 70634, 158713, 356625, 801329, 1800570, 4045844, 9090929, 20427132, 45899349, 103134901, 231742019, 520719590, 1170046298, 2629070167, 5907467042, 13273957953, 29826312781, 67019116473, 150590587774

Offset

1,1

Links

Table of n, a(n) for n=1..31.

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

Formula

G.f.: x*(4*x^3-5*x^2-9*x+9)/(x^3-x^2-2*x+1). - Alois P. Heinz, Apr 15 2025

Crossrefs

Cf. A052268, A100062, A383070, A383071, A383072, A383077, A383078.

Sequence in context: A393819 A053456 A144424 * A359038 A282269 A205380

Adjacent sequences: A383076 A383077 A383078 * A383080 A383081 A383082

Keyword

nonn,easy

Author

Edwin Hermann, Apr 15 2025

Extensions

More terms from Alois P. Heinz, Apr 15 2025

Status

approved