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

2, 3, 11, 5

Offset

1,1

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

Links

Table of n, a(n) for n=1..4.

Prog

(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

Crossrefs

Cf. A093324.

Sequence in context: A083125 A332661 A031335 * A030391 A244496 A039654

Adjacent sequences: A084740 A084741 A084742 * A084744 A084745 A084746

Keyword

nonn

Author

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

Status

approved