OFFSET
1,2
LINKS
Zak Seidov, Table of n, a(n) for n = 1..1000
FORMULA
a(n) = (1/2)*(sqrt(2*A076727(n) - k^2) - k), k = 3.
MAPLE
A224870:=n->`if`(isprime(n^2 + (n+3)^2), n, NULL): seq(A224870(n), n=1..10^3); # Wesley Ivan Hurt, Feb 11 2017
MATHEMATICA
k = 3; Select[Range[500], PrimeQ[#^2 + (# + k)^2]&]
PROG
(PARI) isok(n) = isprime(n^2 + (n+3)^2); \\ Michel Marcus, Feb 13 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, Jul 22 2013
STATUS
approved