A213880 a(n) = sum of n-digit numbers with distinct nonzero digits.

45, 3960, 279720, 16798320, 839991600, 33599966400, 1007999899200, 20159999798400, 201599999798400

Offset

1,1

References

H. E. Dudeney, Amusements in Mathematics, Dover, NY, 1917, pp. 17, 160.

Links

Table of n, a(n) for n=1..9.

H. E. Dudeney, Amusements in Mathematics [Gutenberg Project Etext]

Formula

a(n) = 5*(10^n - 1)*8!/(9 - n)!.

Mathematica

Table[5*(10^n - 1)*8!/(9 - n)!, {n, 9}]

Prog

(Magma) [ 5*(10^n-1)*Factorial(8)/Factorial(9-n) : n in [1..9]]
(PARI) vector(9, n, 5*(10^n-1)*8!/(9-n)!)

Crossrefs

Sequence in context: A184286 A130017 A025755 * A113630 A143004 A004707

Adjacent sequences: A213877 A213878 A213879 * A213881 A213882 A213883

Keyword

base,easy,fini,full,nonn

Author

Arkadiusz Wesolowski, Jun 23 2012

Status

approved