A289356 Least number k such that n^2 + n + k is prime.
2, 1, 1, 1, 3, 1, 1, 3, 1, 7, 3, 5, 1, 9, 1, 1, 5, 1, 5, 3, 1, 1, 3, 5, 1, 3, 7, 1, 9, 7, 7, 5, 5, 1, 3, 17, 29, 3, 1, 7, 17, 1, 5, 9, 7, 11, 17, 11, 5, 9, 1, 5, 11, 17, 1, 3, 11, 1, 11, 1, 11, 11, 1, 17, 17, 7, 1, 5, 11, 1, 3, 1, 5, 5, 7, 1, 5, 1, 1, 3, 1, 11, 17, 5, 11, 11
Offset: 0
Keywords
Links
- Robert Israel, Table of n, a(n) for n = 0..10000
Programs
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Maple
seq(nextprime(n^2+n)-(n^2+n), n=0..100); # Robert Israel, Jul 05 2017
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Mathematica
Table[k = 1; While[! PrimeQ[n^2 + n + k], k++]; k, {n, 0, 85}] (* Michael De Vlieger, Jul 04 2017 *) -
PARI
for(n=0,85,k={my(k=1);while(!isprime(n^2+n+k),k++);k;};print1(k", "))
Comments