login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A265325 Number of n-digit decimal numbers with leading zeros allowed where no digit appears exactly twice. 3
10, 90, 730, 5410, 37900, 264250, 1908910, 14322520, 110305720, 875799550, 7203731050, 60866700940, 527138423380, 4696469283970, 42797376850150, 397903278667600, 3783002076771760, 36604891556846470, 360117919584474850, 3603555076712108500 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

Math Stackexchange, Marko Riedel et al., N digit numbers with no digit appearing exactly twice.

FORMULA

E.g.f.: Sum_{q=1..N} C(10,q)*(exp(z)-z^2/2-1)^q.

E.g.f.: (exp(z)-z^2/2)^10.

EXAMPLE

Computing the value for n=1 the ten one-digit numbers 0-9 all qualify.

Computing the value for n=2 of two-digit numbers 00-99 all qualify except those consisting of a double digit (00, 11, ..., 99).

MAPLE

STNE2 := (n, k)->n!*coeftayl((exp(z)-z^2/2-1)^k/k!, z=0, n);

a(N) := N -> add(combinat:-binomial(10, q)*STNE2(N, q)*q!, q = 1 .. N)

CROSSREFS

Cf. A272501, A272502, A272503.

Sequence in context: A319893 A319874 A159733 * A038726 A009454 A231530

Adjacent sequences:  A265322 A265323 A265324 * A265326 A265327 A265328

KEYWORD

nonn,base

AUTHOR

Marko Riedel, Apr 30 2016

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 20 20:50 EDT 2019. Contains 326155 sequences. (Running on oeis4.)