A283430 Starting with a(1) = 1, a(n) = smallest nonnegative integer not yet in the sequence such that the digits of a(n-1) and a(n) together are all distinct except for one digit that appears twice.

1, 10, 12, 2, 11, 3, 13, 14, 4, 22, 5, 15, 16, 6, 26, 20, 21, 17, 7, 27, 23, 24, 25, 28, 8, 18, 19, 9, 29, 32, 30, 31, 34, 35, 36, 37, 38, 39, 43, 40, 33, 41, 42, 45, 46, 47, 48, 49, 54, 50, 44, 51, 52, 53, 56, 57, 58, 59, 65, 60, 55, 61, 62, 63, 64, 67, 68

Offset

1,2

Links

Table of n, a(n) for n=1..67.

Example

The terms a(5) = 11, a(6) = 3 are allowed since in both terms altogether the digit 1 appears twice. On the contrary, a(n-1) = 11, a(n) = 12 are not allowed since the digit 1 appears three times. Also a(n-1) = 11, a(n) = 22 are not allowed since two digits (not one) appear twice.

Mathematica

L = {1}; While[Length[L] < 100, k=2; While[ MemberQ[L, k] || (d = Plus @@ DigitCount[{k, L[[-1]]}]; ! SubsetQ[{0, 1, 2}, d] || Count[d, 2] != 1), k++]; AppendTo[L, k]]; L (* Giovanni Resta, May 22 2017 *)

Crossrefs

Cf. A287205.

Sequence in context: A287875 A064795 A273463 * A278856 A316914 A350444

Adjacent sequences: A283427 A283428 A283429 * A283431 A283432 A283433

Keyword

nonn,fini,base

Author

Enrique Navarrete, May 15 2017

Extensions

Data corrected by Giovanni Resta, May 22 2017

Status

approved