A167039 Squares that remain squares when prefixed with a 5.

625, 62500, 6250000, 58140625, 625000000, 5814062500, 6703515625, 62500000000, 581406250000, 670351562500, 6250000000000, 58140625000000, 67035156250000, 539545791015625, 625000000000000, 5814062500000000, 6703515625000000, 53954579101562500

Offset

1,1

Comments

Numbers s of A000290 such that 5*10^A055642(s)+s is also in A000290.

Links

Chai Wah Wu, Table of n, a(n) for n = 1..1000

Example

625 = 25^2 is a square and becomes the square 5625 = 75^2 if a 5 is attached in front of its decimal representation.

Crossrefs

Sequence in context: A017224 A106321 A017332 * A265932 A017452 A223230

Adjacent sequences: A167036 A167037 A167038 * A167040 A167041 A167042

Keyword

nonn,base

Author

Claudio Meller, Oct 27 2009

Extensions

Keyword:base added by R. J. Mathar, Oct 28 2009

More terms from Chai Wah Wu, Sep 11 2014

Status

approved