OFFSET

1,1

COMMENTS

A072883 is the main entry for the problem of finding the smallest prime of the form k^n + n: many such k (up to n = 750 and beyond) are listed in the b-file there, but the corresponding primes are too large to list more of them here. - M. F. Hasler, Jul 07 2024

LINKS

Barry Carter, Tweaks to A084047 (request), in r/OEIS on reddit.com, May 8, 2023.

FORMULA

In general, if n+1 is prime, then a(n) = n + 1 = 1^n + n.

EXAMPLE

a(2) = 3 = 1^2 + 2; a(4) = 5 = 1^4 + 4; a(6) = 7 = 1^6 + 6.

MATHEMATICA

f[n_] := f[n] = Module[{m=1}, While[!PrimeQ[m^n + n], m++]; Return[m^n + n]]; (* from Barry Carter in r/OEIS, May 08 2023, cf. link. - M. F. Hasler, Jul 07 2024 *)

PROG

CROSSREFS

KEYWORD

nonn,less

AUTHOR

Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), May 26 2003

EXTENSIONS

Corrected and extended by Ray Chandler, Jun 16 2003

One more term from Michel Marcus, Mar 27 2020

STATUS

approved