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A349900 Primes of the form x^2 + (y^2+1)^2. 2
5, 13, 17, 29, 37, 41, 53, 61, 89, 101, 109, 149, 173, 181, 197, 229, 257, 269, 281, 293, 349, 353, 389, 401, 433, 461, 509, 541, 577, 601, 613, 677, 701, 733, 757, 773, 797, 809, 829, 941, 1049, 1061, 1093, 1117, 1181, 1229, 1297, 1301 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Merikoski proved that there are infinitely many primes of this form, and that the order of growth of the sequence up to x is x^(3/4)/log x. (His method did not provide enough Type II information to prove that there is a C such that there are ~ C*x^(3/4)/log x.)

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Jori Merikoski, The polynomials X^2+(Y^2+1)^2 and X^2+(Y^3+Z^3)^2 also capture their primes, arXiv:2112.03617 [math.NT], 2021.

FORMULA

a(n) ≍ (n log n)^(4/3).

PROG

(PARI) list(lim)=my(v=List()); lim\=1; for(y=0, sqrtint(sqrtint(lim-1)-1), my(t=(y^2+1)^2); forstep(x=2-y%2, sqrtint(lim-t), 2, my(p=x^2+t); if(isprime(p), listput(v, p)))); Set(v)

(PARI) is(n)=if(n<5 || !isprime(n), return(0)); for(y=0, sqrtint(sqrtint(n-1)-1), if(isprime(n-(y^2+1)^2), return(1))); 0

CROSSREFS

Subsequence of A002144.

Cf. A028916, A350687.

Sequence in context: A280084 A319287 A192592 * A347163 A111055 A307096

Adjacent sequences:  A349897 A349898 A349899 * A349901 A349902 A349903

KEYWORD

nonn

AUTHOR

Charles R Greathouse IV, Jan 11 2022

STATUS

approved

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Last modified July 3 08:00 EDT 2022. Contains 355031 sequences. (Running on oeis4.)