A331543 Squares using only decimal digits 0,1,2,3.

0, 1, 100, 121, 10000, 10201, 12100, 12321, 22201, 123201, 130321, 1000000, 1002001, 1020100, 1022121, 1210000, 1212201, 1232100, 1320201, 2220100, 3101121, 12320100, 13032100, 100000000, 100020001, 100200100, 100220121, 102010000, 102030201, 102212100, 102232321, 103002201, 121000000, 121022001, 121220100

Offset: 1

Author

Robert Israel, Jan 19 2020

Keywords

• nonn
• base

Comments

If n is a member then so is 100*n.

All terms == 0, 1, 100, 121, 201 or 321 (mod 1000).

Examples

			a(3) = 100 is a member because 100 = 10^2 and 100 has no digits > 3.
		

Links

• Robert Israel, Table of n, a(n) for n = 1..400

Crossrefs

Cf. A030174.

Programs

Maple

Res:= NULL: count:= 0:
for k from 0 while count < 50 do
  for j in [0,1,100,121,201,321] do
    L:= convert(k,base,4);
    x:= add(L[i]*10^(i-1),i=1..nops(L))*1000+j;
    if issqr(x) then count:= count+1; Res:= Res, x fi
od od:
Res;