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A064756 a(n) = n*10^n - 1. 4
9, 199, 2999, 39999, 499999, 5999999, 69999999, 799999999, 8999999999, 99999999999, 1099999999999, 11999999999999, 129999999999999, 1399999999999999, 14999999999999999, 159999999999999999, 1699999999999999999, 17999999999999999999 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
Amelia Carolina Sparavigna, Some Groupoids and their Representations by Means of Integer Sequences, International Journal of Sciences (2019) Vol. 8, No. 10.
MAPLE
k:= 10; f:= gfun:-rectoproc({1 + (k-1)*n + k*n*a(n-1) - (n-1)*a(n) = 0, a(1) = k-1}, a(n), remember): map(f, [$1..20]); # Georg Fischer, Feb 19 2021
MATHEMATICA
Array[# 10^# - 1 &, 18] (* Michael De Vlieger, Jan 14 2020 *)
PROG
(Magma) [ n*10^n-1: n in [1..20]]; // Vincenzo Librandi, Sep 16 2011
CROSSREFS
For a(n)=n*k^n-1 cf. -A000012 (k=0), A001477 (k=1), A003261 (k=2), A060352 (k=3), A060416 (k=4), A064751 (k=5), A064752 (k=6), A064753 (k=7), A064754 (k=8), A064755 (k=9), this sequence (k=10), A064757 (k=11), A064758 (k=12).
Sequence in context: A157594 A232276 A196910 * A197077 A093708 A052145
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Oct 19 2001
STATUS
approved

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Last modified March 29 06:44 EDT 2024. Contains 371265 sequences. (Running on oeis4.)