login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A071131 Squares which repeat with at least two full periods when written in base 5. 1
7056, 71824, 17380561, 10479821641, 1695422743056, 3046710023334121, 3484661204178361, 4238552821180561, 16390460540754756, 2341118082098985289, 49597060188790044841, 413921144300672743056, 931719854156507158681, 1149780956458574459881, 1254278391764733006841 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Giovanni Resta, Table of n, a(n) for n = 1..23 (terms < 5^33)

EXAMPLE

268^2 = 71824 = 424|424|4 in base 5.

1302084^2 = 1695422743056 = 210234211|210234211 in base 5.

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[5, #] & /@ Range[15]) (* Giovanni Resta, Aug 01 2018 *)

CROSSREFS

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

Sequence in context: A116332 A234545 A250850 * A238520 A230975 A031582

Adjacent sequences:  A071128 A071129 A071130 * A071132 A071133 A071134

KEYWORD

base,nonn

AUTHOR

Erich Friedman, May 28 2002

EXTENSIONS

a(5)-a(15) from Giovanni Resta, Aug 01 2018

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 17 11:39 EDT 2021. Contains 348048 sequences. (Running on oeis4.)