%I #19 Mar 06 2020 12:02:03
%S 665897,741413,794207,859601,876611,892627,980911,1102249,1116977,
%T 1123879,1129213,1163653,1228543,1237139,1393771,1434553,1453019,
%U 1471079,1513163,1570577,1588133,1608769,1638211,1638743,1645253,1670887,1702933,1704137,1785337
%N Septic hyperartiads: septic artiads (A270800) for which 7 is a 7th power residue.
%H Eric M. Schmidt, <a href="/A270801/b270801.txt">Table of n, a(n) for n = 1..100</a>
%H 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.
%H E. Lehmer, <a href="/A001583/a001583b.pdf">Artiads characterized</a>, J. Math. Anal. Appl. 15 1966 118-131 [annotated and corrected scanned copy]
%o (Sage)
%o def is_septic_hyperartiad(n) :
%o if not (n % 14 == 1 and is_prime(n)) : return false
%o R.<t> = PolynomialRing(GF(n))
%o return 7.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())
%o # _Eric M. Schmidt_, Apr 02 2016
%Y Cf. A001583, A270800.
%K nonn
%O 1,1
%A _N. J. A. Sloane_, Apr 01 2016, typo corrected Apr 02 2016
%E Definition corrected by and more terms from _Eric M. Schmidt_, Apr 02 2016