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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A259411 Numbers n such that 1 - sigma(n) + sigma(n)^2 - sigma(n)^3 + sigma(n)^4 is prime. 3
 2, 6, 11, 19, 33, 35, 37, 47, 57, 68, 79, 81, 82, 88, 118, 121, 129, 145, 157, 162, 179, 217, 226, 241, 245, 257, 258, 260, 262, 289, 306, 332, 378, 393, 430, 434, 441, 461, 465, 466, 473, 474, 477, 483, 485, 490, 499, 504, 509, 512, 518, 526, 528, 533, 550 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Robert Price, Table of n, a(n) for n = 1..1017 MAPLE with(numtheory): A259411:=n->`if`(isprime(1-sigma(n)+sigma(n)^2-sigma(n)^3+sigma(n)^4), n, NULL): seq(A259411(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[10, DivisorSigma[1, #]]] &] PROG (MAGMA) [n: n in [1..600] | IsPrime(1 - DivisorSigma(1, n) + DivisorSigma(1, n)^2 - DivisorSigma(1, n)^3 + DivisorSigma(1, n)^4)]; // Vincenzo Librandi, Jun 27 2015 (PARI) is(n)=my(s=sigma(n)); isprime(s^4-s^3+s^2-s+1) \\ Charles R Greathouse IV, May 22 2017 CROSSREFS Cf. A000203, A259410, A259412. Sequence in context: A163324 A317186 A048204 * A058760 A239071 A085573 Adjacent sequences:  A259408 A259409 A259410 * A259412 A259413 A259414 KEYWORD easy,nonn AUTHOR Robert Price, Jun 26 2015 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 June 29 17:41 EDT 2022. Contains 354913 sequences. (Running on oeis4.)