A225560 Least numbers k for each base b >= 2 such that N = b^(2^n) + k is prime for 7 consecutive values from n = 0 to n = 6

66747, 18248, 53097, 2037018, 142531, 1691820, 1322535, 1659002, 266251, 6185640, 95075, 2518780, 657645, 325528, 71971, 2533260, 21494113, 682318, 3114879, 6523742, 9196027, 3588090, 12492473, 816078, 14837001, 12060370, 2933065, 12212058, 3122953

Offset

2,1

Comments

Generalized Fermat numbers of the form b^(2^n) + k

Links

Table of n, a(n) for n=2..30.

Prog

(PARI) for(b=2, 30, if(b%2==0, a=1, a=0); forstep(k=a, 10^8, 2, i=0; for(n=0, 6, m=b^2^n+k; if(isprime(m), i++; if(i>6, print1(k, ", "); next(3))))))

Crossrefs

Cf. A070694, A225321, A225492

Sequence in context: A237925 A251057 A256002 * A234402 A235024 A235245

Adjacent sequences: A225557 A225558 A225559 * A225561 A225562 A225563

Keyword

nonn

Author

Robin Garcia, May 10 2013

Status

approved