A089362 Numbers n such that n^2 - 5n + 5 is prime.

5, 6, 7, 8, 9, 11, 12, 13, 14, 16, 18, 19, 22, 23, 24, 27, 29, 31, 33, 34, 38, 41, 42, 44, 47, 48, 49, 51, 53, 56, 57, 58, 59, 62, 63, 67, 68, 69, 71, 73, 79, 86, 88, 89, 92, 96, 97, 99, 103, 104, 106, 117, 118, 123, 128, 129, 133, 134, 137, 141, 143, 144, 147, 148, 151, 152, 156, 157, 158, 161, 162, 163, 166, 167, 172

Offset: 1

Author

Giovanni Teofilatto, Dec 27 2003

Keywords

• easy
• nonn

References

• M. Cerasoli, F. Eugeni and M. Protasi, Elementi di Matematica Discreta, Bologna 1988.
• Emanuele Munarini and Norma Zagaglia Salvi, Matematica Discreta, UTET, CittaStudiEdizioni, Milano 1997.

Crossrefs

Cf. A002328.

Programs

PARI

is(n)=isprime(n^2-5*n+5) \\ Charles R Greathouse IV, Jun 13 2017

Formula

a(n) = A002328(n)+2.

Extensions

Corrected and extended by Georg Fischer, Jun 20 2020