A136884 Numbers k such that k and k^2 use only the digits 0, 2, 3, 4 and 7.

0, 2, 20, 200, 2000, 20000, 200000, 2000000, 4740332, 20000000, 27204302, 47403320, 200000000, 272043020, 474033200, 2000000000, 2702734302, 2720430200, 4477474032, 4740332000, 20000000000, 27027343020, 27204302000, 44774740320, 47227474032, 47403320000, 200000000000, 270273430200, 272043020000, 447747403200

Offset

1,2

Comments

Generated with DrScheme.

Once any term appears that is not a multiple of 10, every multiple of that term by a power of 10 is also a term, i.e., new terms can be generated by appending any number of zeros to previous terms. - Harvey P. Dale, May 02 2021

Links

Jonathan Wellons, Table of n, a(n) for n = 1..55

J. Wellons, Tables of Shared Digits [archived]

Example

47333227304302^2 = 2240434407040720377707707204.

Mathematica

With[{c={0, 2, 3, 4, 7}}, Select[FromDigits/@Tuples[c, 12], SubsetQ[ c, IntegerDigits[ #^2]]&]] (* Harvey P. Dale, May 02 2021 *)

Crossrefs

Sequence in context: A085586 A322298 A136902 * A093136 A037519 A037722

Adjacent sequences: A136881 A136882 A136883 * A136885 A136886 A136887

Keyword

base,nonn

Author

Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008

Status

approved