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!)
A280134 Number of primes of the form 4(n - k - 1) + 3 where 0 <= k and prime of the form 4k + 3 <= n. 1

%I #15 Dec 27 2016 23:12:30

%S 0,0,1,0,1,1,1,1,1,0,1,2,2,1,1,1,2,2,3,2,3,3,2,1,2,2,2,2,1,1,2,2,3,3,

%T 2,2,3,2,3,3,1,4,3,1,4,3,2,3,4,3,2,5,3,2,4,2,4,4,3,4,4,3,3,5,2,2,6,4,

%U 2,5,4,3,6,3,2,3,4,4,5,3,2,6,4,3,5,1,5,6,2,3,4,4,3,6,3,4,8,3,3,4,3,3,5,2,2,6,4,3,6,5

%N Number of primes of the form 4(n - k - 1) + 3 where 0 <= k and prime of the form 4k + 3 <= n.

%C (1) Conjecture: a(n) > 0 for n >= 11.

%C (2) Conjecture: A278287(n) > 0 for n >= 11.

%C Conjecture (1) and conjecture (2) are first and second parts of Goldbach-like conjecture in A001031.

%e a(12) = 2 because 4*(12-0-1)+3 = 47 and 4*0+3 = 3 are primes where 3 < 12 and 4*(12-1-1)+3 = 43 and 4*1+3 = 7 are primes where 7 < 12.

%Y Cf. A001031, A002144, A278287.

%K nonn

%O 1,12

%A _Juri-Stepan Gerasimov_, Dec 26 2016

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 April 25 08:27 EDT 2024. Contains 371964 sequences. (Running on oeis4.)