OFFSET
1,1
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..10000
MATHEMATICA
fQ[n_] := Block[{c = DigitCount@ n}, And[Plus @@ Take[c, {1, 3}] == 0, Last@ c == 0, c[[4]] > 0, c[[9]] > 0]]; Select[Range@ 1000000, fQ@ # && fQ[#^2] &] (* Michael De Vlieger, May 05 2015 *)
PROG
(PARI) is(n) = vecmin(digits(n))==4 && vecmin(digits(n^2))==4 && vecmax(digits(n))==9 && vecmax(digits(n^2))==9
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Felix Fröhlich, May 03 2015
STATUS
approved