A160154 10^n-9n for n>=1

0, 1, 82, 973, 9964, 99955, 999946, 9999937, 99999928, 999999919, 9999999910, 99999999901, 999999999892, 9999999999883, 99999999999874, 999999999999865, 9999999999999856, 99999999999999847, 999999999999999838

Offset

0,3

Comments

a(n) is the number of positive integers less than or equal to 10^n that have at least two distinct digits.

References

Miklos Bona, Introduction to Enumerative Combinatorics, McGraw-Hill,2007,p.5

Links

Table of n, a(n) for n=0..18.

Formula

O.g.f.: (x+70x^2+10x^3)/((1-x)^2*(1-10x)) E.g.f.: exp(10x)-9x*exp(x)-1

Mathematica

CoefficientList[Series[Exp[10 x] - 9 x*Exp[x] - 1, {x, 0, 20}], x]* Table[n!, {n, 0, 20}]

Crossrefs

For n>=1, a(n)=A011557-A008591

Sequence in context: A356536 A282159 A263812 * A093282 A085439 A282155

Adjacent sequences: A160151 A160152 A160153 * A160155 A160156 A160157

Keyword

nonn

Author

Geoffrey Critzer, May 03 2009

Status

approved