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A271263 Septic artiads (A270800) congruent to 1 mod 98 and for which 2 is a 7th power residue.

%I A271263 #12 Mar 07 2020 05:40:45
%S A271263 874651,941879,1074277,1080451,1396697,2024387,2546237,2807603,
%T A271263 3267419,3324847,3436273,3465673,3851009,4150301,4219979,4367567,
%U A271263 4651963,4762507,5173813,5308759,5398919,5474477,5552191,5710363,6248579,6391267,6575507,6627251,6791107
%N A271263 Septic artiads (A270800) congruent to 1 mod 98 and for which 2 is a 7th power residue.
%H A271263 Eric M. Schmidt, <a href="/A271263/b271263.txt">Table of n, a(n) for n = 1..100</a>
%H A271263 E. Lehmer, <a href="http://dx.doi.org/10.1016/0022-247X(66)90145-4">Artiads characterized</a>, J. Math. Anal. Appl. 15 1966 118-131. See p. 128, Theorem 7.
%H A271263 E. Lehmer, <a href="/A001583/a001583b.pdf">Artiads characterized</a>, J. Math. Anal. Appl. 15 1966 118-131 [annotated and corrected scanned copy]
%o A271263 (Sage)
%o A271263 def isa(n) :
%o A271263     if not (n % 98 == 1 and is_prime(n)) : return False
%o A271263     R.<t> = PolynomialRing(GF(n))
%o A271263     return 2.powermod((n-1)//7, n) == 1 and all(r[0]^((n-1)//7) == 1 for r in (t^3 + t^2 - 2*t - 1).roots())
%Y A271263 Cf. A001583, A270800.
%K A271263 nonn
%O A271263 1,1
%A A271263 _Eric M. Schmidt_, Apr 03 2016