A257085 - OEIS

A257085

Numbers n such that the decimal expansions of both n and n^2 only use the digits 0..6.

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,3

LINKS

Danny Rorabaugh, Table of n, a(n) for n = 1..10000

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).

Cf. A136859, A256633.

Sequence in context: A348937 A117890 A108853 * A334736 A265349 A047433

Adjacent sequences: A257082 A257083 A257084 * A257086 A257087 A257088

KEYWORD

nonn,easy,base

AUTHOR

Danny Rorabaugh, Apr 15 2015

STATUS

approved