A071130 Squares which repeat with at least two full periods when written in base 4.

6241, 378225, 672400, 1320201, 28121809, 302794801, 386554921, 1211179204, 7681646025, 73073443041, 79698371481, 91424593225, 120297291921, 292293772164, 318793485924, 657660987369, 1521820771641, 18145972716481, 72583890865924, 163313754448329

Offset

1,1

Links

Giovanni Resta, Table of n, a(n) for n = 1..80 (terms < 4^38)

Example

79^2 = 6241 = 120|120|1 in base 4.
615^2 = 378225 = 11301|11301 in base 4.

Mathematica

psq[b_, nd_] := Block[{sq={}, r, x}, Do[r = Mod[nd, p]; Do[x = (b^( Floor[nd/p] p) - 1)/(b^p - 1) t  b^r + Floor[t/b^(p - r)]; If[ IntegerQ@ Sqrt@ x, AppendTo[ sq, x]], {t, b^(p - 1), b^p - 1}], {p, nd/2}]; sq]; Union @@ (psq[4, #] & /@ Range[16]) (* Giovanni Resta, Aug 01 2018 *)

Crossrefs

Cf. A071128 (base 2) - A071135 (base 9), A069919 (base 10).

Sequence in context: A200830 A028545 A173943 * A031577 A031757 A195524

Adjacent sequences: A071127 A071128 A071129 * A071131 A071132 A071133

Keyword

base,nonn

Author

Erich Friedman, May 28 2002

Extensions

a(16)-a(20) from Giovanni Resta, Aug 01 2018

Status

approved