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A246392 Numbers n such that Phi(10, n) is prime, where Phi is the cyclotomic polynomial.

%I A246392 #32 Sep 08 2022 08:46:09
%S A246392 2,3,5,10,11,12,16,20,21,22,33,37,38,43,47,48,55,71,75,76,80,81,111,
%T A246392 121,126,131,133,135,136,141,155,157,158,165,176,177,180,203,223,242,
%U A246392 245,251,253,256,257,258,265,268,276,286,290,297,307,322,323,342,361,363,366,375,377,385,388,396,411
%N A246392 Numbers n such that Phi(10, n) is prime, where Phi is the cyclotomic polynomial.
%C A246392 Numbers n such that (n^5+1)/(n+1) is prime, or numbers n such that A060884(n) is prime.
%H A246392 Ray Chandler, <a href="/A246392/b246392.txt">Table of n, a(n) for n = 1..10000</a> (first 893 terms from Robert Price)
%H A246392 OEIS Wiki, <a href="https://oeis.org/wiki/Cyclotomic Polynomials at x=sigma(n)">Cyclotomic Polynomials at x=sigma(n)</a>
%p A246392 A246392:=n->`if`(isprime((n^5+1)/(n+1)),n,NULL): seq(A246392(n), n=1..500); # _Wesley Ivan Hurt_, Nov 15 2014
%t A246392 Select[Range[700], PrimeQ[(#^5 + 1) / (# + 1)] &] (* _Vincenzo Librandi_, Nov 14 2014 *)
%o A246392 (PARI) for(n=1,10^3,if(isprime(polcyclo(10,n)),print1(n,", "))); \\ _Joerg Arndt_, Nov 13 2014
%o A246392 (Magma) [n: n in [1..500]| IsPrime((n^5+1) div (n+1))]; // _Vincenzo Librandi_, Nov 14 2014
%Y A246392 Cf. A008864 (1), A006093 (2), A002384 (3), A005574 (4), A049409 (5), A055494 (6), A100330 (7), A000068 (8), A153439 (9), this sequence (10), A162862 (11), A246397 (12), A217070 (13), A006314 (16), A217071 (17), A164989 (18), A217072 (19), A217073 (23), A153440 (27), A217074 (29), A217075 (31), A006313 (32), A097475 (36), A217076 (37), A217077 (41), A217078 (43), A217079 (47), A217080 (53), A217081 (59), A217082 (61), A006315 (64), A217083 (67), A217084 (71), A217085 (73), A217086 (79), A153441 (81), A217087 (83), A217088 (89), A217089 (97), A006316 (128), A153442 (243), A056994 (256), A056995 (512), A057465 (1024), A057002 (2048), A088361 (4096), A088362 (8192), A226528 (16384), A226529 (32768), A226530 (65536).
%Y A246392 Cf. A060884, A085398, A259257.
%K A246392 nonn
%O A246392 1,1
%A A246392 _Eric Chen_, Nov 13 2014