A110397 a(n) = (10^k - n)(10^k + n), where k is the number of digits in n.

99, 96, 91, 84, 75, 64, 51, 36, 19, 9900, 9879, 9856, 9831, 9804, 9775, 9744, 9711, 9676, 9639, 9600, 9559, 9516, 9471, 9424, 9375, 9324, 9271, 9216, 9159, 9100, 9039, 8976, 8911, 8844, 8775, 8704, 8631, 8556, 8479, 8400, 8319, 8236, 8151, 8064, 7975

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Example

a(3)=(10-3)(10+3)=91; a(11)=(100+11)(100-11)=111*89=9879.

Maple

s:=proc(m) nops(convert(m, base, 10)) end: a:=n->(10^(s(n))-n)*(10^(s(n))+n): seq(a(n), n=1..55); # s gives number of digits # Emeric Deutsch, Aug 01 2005

Mathematica

Table[Times@@(10^IntegerLength[n]+{n, -n}), {n, 50}] (* Harvey P. Dale, May 31 2015 *)

Crossrefs

Sequence in context: A305046 A316732 A033419 * A298509 A185504 A304009

Adjacent sequences: A110394 A110395 A110396 * A110398 A110399 A110400

Keyword

base,easy,nonn

Author

Amarnath Murthy, Jul 29 2005

Extensions

More terms from Emeric Deutsch, Aug 01 2005

Status

approved