OFFSET
0,2
COMMENTS
The leading numbers free of the trailing end 0's in the entries of sequence a(n) are the corresponding powers of 2 written in base 5, i.e., A000866(n). - Lekraj Beedassy, Oct 26 2010
The first formula follows from the fact that the quinary representation of 10^n - 1 is equal to the concatenation of the quinary representation of 2^n - 1 with four times the n-th repunit; so the successor 10^n is the concatenation of 2^n with n zeros. See the Regan link. - Washington Bomfim, Dec 24 2010
LINKS
Rick Regan, Nines in quinary
FORMULA
a(n) = A000866(n) followed by n zeros.
MATHEMATICA
FromDigits[IntegerDigits[#, 5]]&/@(10^Range[0, 20]) (* Harvey P. Dale, Feb 03 2019 *)
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Henry Bottomley, Jun 27 2000
EXTENSIONS
More terms from James A. Sellers, Jul 04 2000
STATUS
approved