login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 60th year, we have over 367,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A136904 Numbers k such that k and k^2 use only the digits 0, 2, 4, 6 and 8. 4
0, 2, 8, 20, 22, 68, 80, 200, 202, 220, 262, 668, 680, 800, 2000, 2002, 2020, 2022, 2200, 2202, 2620, 6668, 6680, 6800, 8000, 8262, 20000, 20002, 20020, 20022, 20200, 20220, 20602, 22000, 22002, 22020, 24622, 26200, 66668, 66680, 66800, 68000, 80000, 82620, 200000, 200002, 200020, 200022, 200200, 200202, 200220, 202000, 202002, 202200, 206020 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Generated with DrScheme.
Subsequence of A014263. - Michel Marcus, Oct 04 2013
LINKS
EXAMPLE
828268460602^2 = 686028642828006826202404.
PROG
(PARI) evdigs(n) = {if (n==0, return (1)); digs = digits(n); for (i = 1, #digs, if (digs[i] % 2, return (0)); ); return (1); }
isok(n) = evdigs(n) && evdigs(n^2); \\ Michel Marcus, Oct 04 2013
CROSSREFS
Sequence in context: A227399 A327098 A030097 * A043002 A108180 A233571
KEYWORD
base,nonn
AUTHOR
Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008
STATUS
approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 8 17:58 EST 2023. Contains 367680 sequences. (Running on oeis4.)