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%I #26 Sep 18 2018 12:14:52
%S 6,32,189,1410,10751,88118,745582,6456835,56988601,510007598,
%T 4615215645
%N Number of primes of the form b^2 + b + 1 for b <= 10^n.
%e a(1) = 6 because there are 6 primes of the form b^2 + b + 1 for b <= 10: 3, 7, 13, 31, 43 and 73.
%o (PARI) {a(n) = sum(k=0, 10^n, isprime(k^2+k+1))}
%o (Python)
%o from sympy import isprime
%o def A319228(n):
%o c, b, b2, n10 = 0, 1, 3, 10**n
%o while b <= n10:
%o if isprime(b2):
%o c += 1
%o b += 1
%o b2 += 2*b
%o return c # _Chai Wah Wu_, Sep 17 2018
%Y Cf. A002383, A002384, A206709.
%K nonn,more
%O 1,1
%A _Seiichi Manyama_, Sep 14 2018
%E a(10) from _Chai Wah Wu_, Sep 17 2018
%E a(11) from _Chai Wah Wu_, Sep 18 2018
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