The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A266962 Numbers n such that (2^(n+8) * 5^(n+5) - 409949) / 9 is prime (n > 0). 0
 5, 65, 66, 168, 689, 1200, 1526, 1986, 7751 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Numbers n such that '43339' appended to n times the digit 8 is prime. a(n) mod 7 <= 5 (zero or prime <= 5). LINKS Table of n, a(n) for n=1..9. EXAMPLE 5 appears because 8888843339 ('8' concatenated 5 times and prepended to '43339') is prime. MATHEMATICA Select[ Range[2000], PrimeQ[(2^(#+8)*5^(#+5) - 409949) / 9] &] (* Or *) Select[ Range[2000], PrimeQ[2*(2^(#+7)*5^(#+5) - 204979) / 9 + 1] &] PROG (PARI) is(n) = ispseudoprime((2^(n+8)*5^(n+5) - 409949) / 9); \\ Altug Alkan, Jan 15 2016 (Magma) [n: n in [0..500] |IsPrime((2^(n+8)*5^(n+5)-409949) div 9)]; // Vincenzo Librandi, Jan 16 2016 CROSSREFS Cf. A266421. Sequence in context: A351020 A238631 A220557 * A126955 A091105 A234335 Adjacent sequences: A266959 A266960 A266961 * A266963 A266964 A266965 KEYWORD nonn,base,more AUTHOR Mikk Heidemaa, Jan 07 2016 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified September 17 04:04 EDT 2024. Contains 375984 sequences. (Running on oeis4.)