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Positive integers n such that there is no triple of primes (p, q, r) satisfying p+q^2+r^3=n.
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%I #9 Jan 19 2019 04:15:43

%S 1,2,3,4,5,6,7,8,9,10,11,12,13,16,18,21,26,27,32,37,45,51,61,66,82,

%T 108,127,178,186,192,234,252,276,306,332,336,351,402,468,582,606,612,

%U 622,642,666,702,712,738,762,798,816,822,864,882,906,930,996,1018,1032

%N Positive integers n such that there is no triple of primes (p, q, r) satisfying p+q^2+r^3=n.

%e For p=2, p+p^2+p^3 = 14 = A181149(1), so 14 is the first value not to be in the sequence.

%o (PARI) nbt(n) = {nb = 0; forprime(p=2, n, forprime(q=2, n, if (p+q^2 > n, break); forprime(r=2, n, if (p+q^2+r^3 > n, break); if (p+q^2+r^3 == n, nb++);););); nb;}

%o isok(n) = nbt(n)==0;

%Y Cf. A181149, A261887.

%K nonn

%O 1,2

%A _Michel Marcus_, Sep 05 2015