%I #34 Mar 15 2015 20:13:24

%S 0,41459,35,9569200211,2673413,10596486211,1885511821439,235,12722173,

%T 1971782729,133617287,14873,1465,1606870609,4247,129015968122421,

%U 526673,835,1079115301,12148589879,12351683,36947690849,6385,5809

%N Least k such that n^k mod k = (n-1)^2, or 0 if no such k exists.

%e a(2) = A036236(1) = 0,

%e a(3) = A078457(2^2) = 41459,

%e a(4) = A119678(3^2) = 35,

%e a(5) = A119679(4^2) = 9569200211,

%e a(6) = A127816(5^2) = 2673413,

%e a(7) = A119715(6^2) = 10596486211,

%e a(8) = A119714(7^2) = 1885511821439,

%e a(9) = A127817(8^2) = 235,

%e a(10) = A127818(9^2) = 12722173,

%e a(11) = A127819(100) = 1971782729,

%e a(12) = A127820(121) = 133617287,

%e a(13) = A127821(144) = 14873,

%e a(14) = A128154(169) = 1465,

%e a(15) = A128155(196) = 1606870609,

%e a(16) = A128156(225) = 4247,

%e a(17) = A128157(256) = 129015968122421,

%e a(18) = A128158(289) = 526673,

%e a(19) = A128159(324) = 835,

%e a(20) = A128160(361) = 1079115301,

%e a(21) = A128361(400) = 12148589879,

%e a(22) = A128362(441) = 12351683,

%e a(23) = A128363(484) = 36947690849,

%e a(24) = A128364(529) = 6385,

%e a(25) = A128365(576) = 5809,

%e a(26) = A128366(625) > 10^15,

%e a(27) = A128367(676) = 299651,

%e a(28) = A128368(729) > 10^14,

%e a(29) = A128369(784) = 2645,

%e a(30) = A128370(841) = 13633321649263,

%e a(31) = A128371(900) = 1051624907,

%e a(32) = A128372(961) = 725521, etc.

%Y Cf. A128148, A128149, A128172, A036236, A078457, A119678, A119679, A127816, A119715, A119714, A127817, A127818, A127819, A127820, A127821, A128154, A128155, A128156, A128157, A128158, A128159, A128160, A128361, A128362, A128363, A128364, A128365, A128366, A128367, A128368, A128369, A128370, A128371, A128372.

%K hard,nonn

%O 2,2

%A _Alexander Adamchuk_, Feb 16 2007, May 06 2007

%E More terms from _Alexander Adamchuk_, Dec 24 2007

%E a(13), a(14), a(16), a(18), a(19), a(24), a(25), a(27), a(29), a(32) from _Alexander Adamchuk_, Feb 17 2008

%E Corrected A-number in cross-reference. Copied a(8) to a(16) from other sequences. - _R. J. Mathar_, Aug 08 2009

%E Edited by _Robert G. Wilson v_, Aug 20 2009

%E a(17) from Joe Crump (joecr(AT)carolina.rr.com), Sep 17 2009.

%E More terms and general editing from _Robert G. Wilson v_, Sep 30 2009

%E a(20)-a(22) from _Robert G. Wilson v_, Oct 17 2009

%E a(23), a(30) from _Max Alekseyev_, Feb 11, Mar 31 2010