|
|
A124189
|
|
Numbers n such that 1 + n + n^3 + n^5 + n^7 + n^9 + n^11 + ... + n^37 + n^39 is prime.
|
|
5
|
|
|
42, 47, 60, 119, 153, 179, 195, 236, 269, 287, 383, 821, 846, 921, 924, 1104, 1181, 1200, 1349, 1806, 1917, 1980, 2015, 2049, 2057, 2369, 2394, 2522, 2660, 2876, 2882, 2940, 2991, 3206, 3311, 3570, 3695, 3741, 3785, 3840, 3944, 3966, 4049, 4148, 4377, 4448
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
LINKS
|
|
|
MAPLE
|
a:= proc(n) option remember; local k;
for k from 1 +`if`(n=1, 1, a(n-1)) while
not isprime(1+(k^41-k)/(k^2-1)) do od; k
end:
|
|
MATHEMATICA
|
Do[If[PrimeQ[1+n+n^3+n^5+n^7+n^9+n^11+n^13+n^15+n^17+n^19 +n^21 +n^23 +n^25 +n^27+n^29+n^31+ n^33+n^35+n^37+n^39], Print[n]], {n, 1, 2400}]
Select[Range[5000], PrimeQ[Total[#^Range[1, 39, 2]] + 1] &] (* Vincenzo Librandi, Jun 27 2014 *)
|
|
PROG
|
(Magma) [n: n in [0..4000] | IsPrime(s) where s is 1+&+[n^i: i in [1..39 by 2]]]; // Vincenzo Librandi, Nov 12 2010, revised Jun 27 2014
(PARI) for(n=1, 10^4, if(ispseudoprime(sum(i=0, 19, n^(2*i+1))+1), print1(n, ", "))) \\ Derek Orr, Jun 24 2014
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|