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A095752
a(n) = (1/9)*(-1+10^n)*(4*n+3)
0
7, 121, 1665, 21109, 255553, 2999997, 34444441, 388888885, 4333333329, 47777777773, 522222222217, 5666666666661, 61111111111105, 655555555555549, 6999999999999993, 74444444444444437, 788888888888888881
OFFSET
1,1
COMMENTS
Numbers with increasingly larger and larger one-digit centers.
REFERENCES
Discovered by Jason Earls.
FORMULA
O.g.f.: -x*(2*x+7)*(5*x-1)/[(-1+x)^2*(-1+10*x)^2]. - R. J. Mathar, Feb 26 2008
CROSSREFS
Sequence in context: A197041 A283625 A372615 * A113267 A274267 A012028
KEYWORD
easy,nonn
AUTHOR
Michael Joseph Halm, Jul 10 2004
STATUS
approved