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A257085
Numbers n such that the decimal expansions of both n and n^2 only use the digits 0..6.
3
0, 1, 2, 4, 5, 6, 10, 11, 12, 15, 16, 20, 21, 25, 32, 34, 35, 40, 45, 46, 50, 51, 55, 56, 60, 65, 66, 100, 101, 102, 105, 106, 110, 111, 112, 115, 116, 120, 121, 125, 142, 145, 146, 150, 152, 155, 156, 160, 162, 200, 201, 204, 205, 206, 210, 211, 215, 216, 225, 231, 235, 245, 246, 250, 251, 252, 254, 255, 256
OFFSET
1,3
LINKS
EXAMPLE
116 is in the list because 116 and 116^2 = 13456 do not use the digits 7, 8 or 9.
182 is not in the list because it uses the digit 8 (even though 182^2 = 33124 would be fine).
253 is not in the list because 253^2 = 6409 uses the digit 9.
MATHEMATICA
Select[Range@ 256, Total@ Take[DigitCount[#], {7, 9}] == 0 && Total@ Take[DigitCount[#^2], {7, 9}] == 0 &] (* Michael De Vlieger, Apr 17 2015 *)
PROG
(PARI) isok(n) = ((vecmax(digits(n)) <= 6) && (vecmax(digits(n^2)) <= 6)) || (n==0); \\ Michel Marcus, Feb 02 2016
CROSSREFS
Cf. A178501 (0..1), A136808(0..2), A136809(0..3), A136810 (0..4), A257086 (0..5).
Sequence in context: A348937 A117890 A108853 * A334736 A265349 A047433
KEYWORD
nonn,easy,base
AUTHOR
Danny Rorabaugh, Apr 15 2015
STATUS
approved