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A084021 Product of n and its 9's complement. 2
8, 14, 18, 20, 20, 18, 14, 8, 0, 890, 968, 1044, 1118, 1190, 1260, 1328, 1394, 1458, 1520, 1580, 1638, 1694, 1748, 1800, 1850, 1898, 1944, 1988, 2030, 2070, 2108, 2144, 2178, 2210, 2240, 2268, 2294, 2318, 2340, 2360, 2378, 2394, 2408, 2420, 2430, 2438 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

There are infinitely many nonzero squares in this sequence; for example a(10^(4n)-10^(2n)) = [10^n*(10^(2n)-1)]^2. - David Wasserman, Dec 07 2004

LINKS

Table of n, a(n) for n=1..46.

FORMULA

a(n) = n*(10^d -1-n), where d is the number of digits in n.

a(n) = n*A061601(n). - David Wasserman, Dec 07 2004

CROSSREFS

Cf. A061601.

Sequence in context: A235143 A179186 A192045 * A138666 A072835 A096229

Adjacent sequences:  A084018 A084019 A084020 * A084022 A084023 A084024

KEYWORD

base,easy,nonn

AUTHOR

Amarnath Murthy, May 23 2003

EXTENSIONS

More terms from David Wasserman, Dec 07 2004

STATUS

approved

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Last modified December 7 07:15 EST 2016. Contains 278841 sequences.