login
A093152
Number of odd composites below 10^n that are congruent to 3 modulo 4.
2
0, 12, 163, 1881, 20192, 210678, 2167602, 22119050, 224575958, 2272470765, 22940965468, 231196012323, 2326967172345, 23397529032871, 235077714312816, 2360380827753871, 23688221418030854, 237630022854838725, 2382971166321456083, 23889590198589663868
OFFSET
1,2
FORMULA
For n>1, a(n) = 25*10^(n-2) - A091099(n) [From Max Alekseyev, May 17 2009]
EXAMPLE
Below 10^2 there are 12 odd composites 3 mod 4 so a(2)=12
KEYWORD
nonn
AUTHOR
Enoch Haga, Mar 24 2004
EXTENSIONS
a(9) from Ryan Propper, Jun 21 2005
a(10)-a(20) from Max Alekseyev, May 17 2009, Oct 08 2013
STATUS
approved