|
|
A258979
|
|
Numbers n such that 1 + sigma(n) + sigma(n)^2 + sigma(n)^3 + sigma(n)^4 is prime.
|
|
3
|
|
|
1, 4, 6, 9, 11, 12, 14, 15, 23, 27, 29, 32, 43, 54, 56, 61, 64, 67, 73, 87, 95, 106, 109, 128, 134, 138, 146, 154, 163, 165, 171, 172, 197, 213, 235, 252, 253, 258, 259, 273, 274, 290, 300, 301, 303, 307, 314, 326, 330, 335, 358, 387, 393, 394, 403, 404, 412
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
LINKS
|
|
|
MAPLE
|
with(numtheory): A258979:=n->`if`(isprime(1 + sigma(n) + sigma(n)^2 + sigma(n)^3 + sigma(n)^4), n, NULL): seq(A258979(n), n=1..1000); # Wesley Ivan Hurt, Jul 09 2015
|
|
MATHEMATICA
|
Select[ Range[10000], PrimeQ[ 1 + DivisorSigma[1, #] + DivisorSigma[1, #]^2 + DivisorSigma[1, #]^3 + DivisorSigma[1, #]^4] & ]
Select[ Range[10000], PrimeQ[ Cyclotomic[5, DivisorSigma[1, #]]] &]
Select[Range[10000], PrimeQ[Total[DivisorSigma[1, #]^Range[0, 4]]]&] (* Harvey P. Dale, Aug 17 2015 *)
|
|
PROG
|
(Magma) [n: n in [1..500] | IsPrime(1 + DivisorSigma(1, n) + DivisorSigma(1, n)^2 + DivisorSigma(1, n)^3 + DivisorSigma(1, n)^4)]; // Vincenzo Librandi, Jun 16 2015
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|