A074268 Primes of the form p^2 - p + 1 where p is prime.

3, 7, 43, 157, 4423, 6163, 19183, 22651, 26407, 37057, 113233, 121453, 143263, 208393, 292141, 375157, 412807, 527803, 590593, 843643, 981091, 1041421, 1193557, 1246573, 1441201, 1514131, 1905781, 2023507, 2397853, 2453923, 2548813, 2626021, 2864557

Offset: 1

Author

Enoch Haga, Jan 16 2004

Keywords

• nonn
• easy

Comments

Note that p^2 - p + 1 = p * phi(p) + 1 when p is prime.

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A065508 (values of p).

Programs

Mathematica

Select[Table[p = Prime[n]; p*EulerPhi[p] + 1, {n, 270}], PrimeQ] (* Arkadiusz Wesolowski, Dec 13 2011 *)
Select[Table[p^2-p+1,{p,Prime[Range[300]]}],PrimeQ] (* Harvey P. Dale, Sep 22 2015 *)