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A147589
Concatenation of 2n-1 digits 1 and n-1 digits 0.
1
1, 1110, 1111100, 1111111000, 1111111110000, 1111111111100000, 1111111111111000000, 1111111111111110000000, 1111111111111111100000000, 1111111111111111111000000000, 1111111111111111111110000000000
OFFSET
1,2
COMMENTS
a(n) is also A147590(n) written in base 2.
FORMULA
a(n) = A138118(n)/10.
a(n) = {[10^(2*n-1)-1]*10^(n-1)}/9, with n>=1. - Paolo P. Lava, Nov 26 2008
G.f.: x*(100*x+1) / ((10*x-1)*(1000*x-1)). - Colin Barker, Jul 08 2014
EXAMPLE
n .......... a(n)
1 ........... 1
2 ......... 1110
3 ....... 1111100
4 ..... 1111111000
5 ... 1111111110000
PROG
(PARI) vector(100, n, 10^(-2+n)*(-10+100^n)/9) \\ Colin Barker, Jul 08 2014
(PARI) Vec(x*(100*x+1)/((10*x-1)*(1000*x-1)) + O(x^100)) \\ Colin Barker, Jul 08 2014
CROSSREFS
KEYWORD
easy,nonn,base
AUTHOR
Omar E. Pol, Nov 08 2008
EXTENSIONS
Keyword:base added by Charles R Greathouse IV, Apr 28 2010
STATUS
approved