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A082465
Least k>=1 such that n^2+kn+1 is prime.
0
1, 1, 1, 3, 1, 1, 3, 1, 3, 3, 7, 1, 11, 1, 1, 5, 1, 3, 3, 1, 1, 6, 3, 1, 3, 7, 1, 6, 3, 3, 5, 4, 1, 3, 7, 7, 3, 1, 9, 3, 1, 4, 3, 3, 3, 5, 3, 6, 3, 1, 5, 3, 3, 1, 3, 4, 1, 3, 1, 7, 5, 1, 3, 3, 3, 1, 3, 7, 1, 9, 1, 7, 9, 9, 1, 12, 1, 1, 5, 1, 5, 3, 19, 3, 3, 4, 7, 3, 1, 1, 5, 3, 3, 11, 3, 4, 11, 6, 1, 3, 1, 3, 11
OFFSET
1,4
PROG
(PARI) a(n)=if(n<0, 0, k=1; while(isprime(n^2+k*n+1)==0, s++); k)
CROSSREFS
Sequence in context: A218825 A035691 A131781 * A226856 A131327 A355899
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Apr 27 2003
STATUS
approved