login
A134230
a(n) = (10^n+1)^2-1.
3
3, 120, 10200, 1002000, 100020000, 10000200000, 1000002000000, 100000020000000, 10000000200000000, 1000000002000000000, 100000000020000000000, 10000000000200000000000, 1000000000002000000000000, 100000000000020000000000000, 10000000000000200000000000000
OFFSET
0,1
COMMENTS
Previous name was: -1 + Sum of first 10^n + 1 odd numbers.
FORMULA
a(n) = (10^n+1)^2-1. - N. J. A. Sloane, Oct 15 2007
a(n) = 110*a(n-1)-1000*a(n-2). - Colin Barker, Jan 27 2015
G.f.: -3*(70*x-1) / ((10*x-1)*(100*x-1)). - Colin Barker, Jan 27 2015
PROG
(PARI) Vec(-3*(70*x-1)/((10*x-1)*(100*x-1)) + O(x^100)) \\ Colin Barker, Jan 27 2015
CROSSREFS
Sequence in context: A214312 A343831 A185554 * A321109 A307936 A308142
KEYWORD
easy,nonn
AUTHOR
Enoch Haga, Oct 14 2007
EXTENSIONS
Edited by N. J. A. Sloane, Oct 15 2007
Offset and name corrected by Arkadiusz Wesolowski, Jun 12 2013
New name (using formula by N. J. A. Sloane) from Joerg Arndt, Jan 27 2015
STATUS
approved