login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A093708 Number of odd nonprime differences of 2 (twin odd nonprimes) below 10^n. 1

%I #10 Apr 24 2020 18:55:37

%S 0,9,200,2748,32041,351174,3729823,38917403,401729439,4117307658,

%T 41988266423,426654761185,4323703591195,43725896820062,

%U 441488068396967,4451827503629449

%N Number of odd nonprime differences of 2 (twin odd nonprimes) below 10^n.

%F Count twin odd nonprimes below 10^n

%F a(n) = 10^n/2 - 2*A006880(n) + A007508(n) + 1. - _Max Alekseyev_, May 11 2005

%e a(2)=9 because under 100 there are 9 twin odd nonprimes, e.g. 27-25=2.

%Y Cf. A093683, A006880, A007508.

%K easy,nonn

%O 1,2

%A _Enoch Haga_, Apr 10 2004

%E More terms from _Max Alekseyev_, May 11 2005

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 29 00:26 EDT 2024. Contains 371264 sequences. (Running on oeis4.)