%I #10 Mar 05 2020 07:03:27

%S 0,1,3,4,9,28,81,136,1216,6561,16768,29889,76545,203392,636417,

%T 1043200,3995649,6082048,24151041,36315136,326481921,689278977,

%U 1487503360,11573190657,76876660737,155240824833,314944159744,785129144320,2035980763137,4857090670593

%N Automorphic numbers: n^2 ends with n in base 6.

%H Eric M. Schmidt, <a href="/A237583/b237583.txt">Table of n, a(n) for n = 1..1000</a>

%e From A201821:

%e a(3) = (3)_6 = 3 since 3^2 = 9 = (13)_6 ends with 3 in base 6.

%e a(4) = (4)_6 = 4 since 4^2 = 16 = (24)_6 ends with 4 in base 6.

%e a(5) = (13)_6 = 9 since 9^2 = 81 = (213)_6 ends with 13 in base 6.

%o (Sage) # See A003226.

%o (PARI) isok(n) = ((n^2-n) % 6^(#digits(n, 6))) == 0; \\ _Michel Marcus_, Mar 08 2014

%Y Cf. A201821 (written in base 6), A003226, A201918, A201919, A201921, A201948.

%K nonn,base

%O 1,3

%A _Eric M. Schmidt_, Feb 09 2014