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This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A126531 Number of base 10 n-digit numbers with adjacent digits differing by five or less.

Original entry on oeis.org

1, 10, 80, 660, 5430, 44692, 367826, 3027314, 24915652, 205062892, 1687725824, 13890462738, 114322452324, 940906242802, 7743925534706, 63734705924048, 524554726284436, 4317234336897124, 35532064407664766, 292438978880594940
Offset: 0

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Author

R. H. Hardin, Dec 28 2006

Keywords

Comments

[Empirical] a(base,n)=a(base-1,n)+11^(n-1) for base>=5n-4; a(base,n)=a(base-1,n)+11^(n-1)-2 when base=5n-5.

Crossrefs

Cf. Base 10 differing by four or less A126505, three or less A126478, two or less A126397, one or less A126364.

Formula

Conjectures from Colin Barker, May 31 2017: (Start)
G.f.: (1 - x)*(1 + 3*x - x^3) / ((1 + x)*(1 - 9*x + 6*x^2 + 3*x^3 - 2*x^4)).
a(n) = 8*a(n-1) + 3*a(n-2) - 9*a(n-3) - a(n-4) + 2*a(n-5) for n>4.
(End)
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Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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