A223077 Positive integers, written in base 3, with the property that if the base-3 representation is reversed the result is twice the original number.

1012, 10212, 102212, 1022212, 10121012, 10222212, 101201012, 102222212, 1012001012, 1021210212, 1022222212, 10120001012, 10212010212, 10222222212, 101200001012, 101210121012, 102120010212, 102212102212, 102222222212, 1012000001012, 1012102121012, 1021200010212, 1022120102212, 1022222222212

Offset

1,1

Comments

For the decimal representations of these same numbers see A173951.

Theorem: The number of terms of length n is equal to A103609(n-2).

Links

N. J. A. Sloane, Table of n, a(n) for n = 1..108

Mathematica

b3rQ[n_]:=FromDigits[Reverse[IntegerDigits[n]], 3]/FromDigits[ IntegerDigits[ n], 3] ==2; Select[FromDigits/@Tuples[{0, 1, 2}, 13], b3rQ]//Quiet (* Harvey P. Dale, Jun 10 2018 *)

Crossrefs

Cf. A173951, A214927.

Sequence in context: A072140 A080467 A023058 * A206191 A249987 A224920

Adjacent sequences: A223074 A223075 A223076 * A223078 A223079 A223080

Keyword

nonn,base

Author

N. J. A. Sloane, Mar 14 2013

Status

approved