A084743 Smallest prime of the form n^k + k, or 0 if no such prime exists.

2, 3, 11, 5

Offset: 1

Author

Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), Jun 15 2003

Keywords

• nonn

Comments

a(5) > 5^18 +18 = 3814697265643. Conjecture: No entry is zero.

See A093324 for the values of k. The next term, a(5) = 5^7954+7954, has 5560 digits and is too large to display here. - T. D. Noe, Oct 05 2007

a(6)-a(10) are 7, 54116956037952111668959660883, 16296287810675888690147565507275025288411747149327490005089123594835050398106693649467179109, 83, and 11, respectively. a(11) > 11^190000 + 190000. See A093324 for the k-values. - Derek Orr, Aug 08 2014

Crossrefs

Cf. A093324.

Programs

PARI

a(n)=for(k=1,8000,s=n^k+k;if(ispseudoprime(s),return(s)))
vector(10,n,a(n)) \\ Derek Orr, Aug 08 2014