OFFSET
1,1
COMMENTS
Equal to primes of the form (k^2+15)/8. Also equal to primes p such that 8*p-15 is a square. - Chai Wah Wu, Jul 14 2014
Primes of A152948. - Klaus Purath, Jan 03 2021
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
MATHEMATICA
Select[Table[(n^2-n+4)/2, {n, 3000}], PrimeQ] (* Vincenzo Librandi, Jul 14 2012 *)
Select[Accumulate[Range[0, 300]]+2, PrimeQ] (* Harvey P. Dale, Feb 05 2019 *)
PROG
(Python)
import sympy
[n*(n+1)/2+2 for n in range(10**6) if sympy.ntheory.primetest.isprime(n*(n+1)/2+2)] # Chai Wah Wu, Jul 14 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Henry Bottomley, Jun 27 2000
STATUS
approved