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!)
A155931 Squares s(n) such that cube(n)-square(n)-1 and cube(n)+square(n)+1 are primes. 1

%I #4 Feb 24 2023 15:54:44

%S 4,9,81,144,900,3249,4356,7569,12321,14400,38025,59049,60516,77841,

%T 142884,145161,186624,202500,221841,230400,356409,423801,576081,

%U 656100,870489,974169,1108809,1838736,1855044,1971216,1979649,1988100,2396304

%N Squares s(n) such that cube(n)-square(n)-1 and cube(n)+square(n)+1 are primes.

%C 2^3-2^2-1=3;2^3+2^2+1=13, 3^3-3^2-1=17;3^3+3^2+1=37, ...

%t lst={};Do[c=n^3;s=n^2;p1=c-s-1;p2=c+s+1;If[PrimeQ[p1]&&PrimeQ[p2],AppendTo[lst,s]],{n,7!}];lst

%t #^2&/@Select[Range[1600],AllTrue[#^3+{-#^2-1,#^2+1},PrimeQ]&] (* _Harvey P. Dale_, Feb 24 2023 *)

%Y Cf. A155929, A155930

%K nonn

%O 1,1

%A _Vladimir Joseph Stephan Orlovsky_, Jan 30 2009

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 19 02:28 EDT 2024. Contains 371782 sequences. (Running on oeis4.)