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

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A134844 Numbers k such that k contains no zero but k^2 contains at least one zero. 19
32, 33, 45, 47, 48, 49, 51, 52, 53, 55, 64, 71, 78, 84, 95, 97, 98, 99, 138, 142, 143, 144, 145, 147, 148, 149, 151, 152, 153, 155, 174, 175, 176, 179, 195, 197, 198, 199, 217, 224, 225, 226, 241, 243, 245, 246, 247, 248, 249, 251, 252, 253, 255, 257, 259, 265 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Contains all numbers with no zero that start with 32. - Robert Israel, Jun 25 2019
LINKS
J. Browkin, Groebner basis.
EXAMPLE
a(1)=32 because 1024 = 32^2.
MAPLE
filter:= proc(n) local L;
L:= convert(n, base, 10);
if member(0, L) then return false fi;
L:= convert(n^2, base, 10);
member(0, L)
end proc:
select(filter, [$1..1000]); # Robert Israel, Jun 25 2019
MATHEMATICA
a = {}; Do[Do[Do[k = 100s + 10n + m; w = IntegerDigits[k^2]; If[MemberQ[w, 0], AppendTo[a, k]], {n, 1, 9}], {m, 1, 9}], {s, 0, 9}]; Union[a]
Select[Range[300], DigitCount[#, 10, 0]==0&&DigitCount[#^2, 10, 0]>0&] (* Harvey P. Dale, Mar 20 2012 *)
CROSSREFS
Sequence in context: A085259 A054032 A134843 * A151983 A022402 A194768
KEYWORD
nonn,base
AUTHOR
Artur Jasinski, Nov 13 2007
EXTENSIONS
Definition clarified by Harvey P. Dale, Mar 20 2012
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 April 19 02:12 EDT 2024. Contains 371782 sequences. (Running on oeis4.)