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!)
A344963 Numbers k such that (2*k+1)*k!+1 is prime. 1

%I #35 Jun 26 2021 17:28:37

%S 0,2,3,5,11,18,68,77,124,173,205,293,1037,1530,1905,2342,3401,4372,

%T 4679,5385

%N Numbers k such that (2*k+1)*k!+1 is prime.

%C a(21) > 10^4.

%p select(k -> isprime((2*k+1)*k!+1), [$0 .. 300])[];

%t Do[If[PrimeQ[(2*k + 1)*Factorial[k] + 1], Print[k]], {k, 0, 3000}]

%o (PARI) for(k=0, 3000, if(isprime((2*k+1)*k!+1), print1(k", ")))

%o (SageMath)

%o for k in range(3000):

%o if is_prime((2*k+1)*factorial(k) + 1):

%o print(k)

%Y Cf. A002981, A344991.

%K nonn,hard,more

%O 1,2

%A _Reza K Ghazi_, Jun 07 2021

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 September 15 19:46 EDT 2024. Contains 375954 sequences. (Running on oeis4.)