A242407 Numbers such that in ternary representation all pairs of adjacent digits have sums not greater than 2.

0, 1, 2, 3, 4, 6, 9, 10, 11, 12, 13, 18, 19, 20, 27, 28, 29, 30, 31, 33, 36, 37, 38, 39, 40, 54, 55, 56, 57, 58, 60, 81, 82, 83, 84, 85, 87, 90, 91, 92, 93, 94, 99, 100, 101, 108, 109, 110, 111, 112, 114, 117, 118, 119, 120, 121, 162, 163, 164, 165, 166, 168

Offset

1,3

Comments

A242400(a(n)) = 0;

A242399(a(n)) = 4*a(n);

numbers m, such that in ternary arithmetic no carry occurs, when 3*m is added to m.

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Ternary.

Wikipedia, Ternary numeral system

Example

Initial terms and their ternary representations, cf. A007089:
.  0 1 2  3  4  6   9  10  11  12  13  18  19  20   27   28   29   30 ..
.  0 1 2 10 11 20 100 101 102 110 111 200 201 202 1000 1001 1002 1010 ..

Mathematica

Select[Range[0, 200], Max[Total/@Partition[IntegerDigits[#, 3], 2, 1]]<3&] (* Harvey P. Dale, Jan 08 2023 *)

Prog

(Haskell)
a242407 n = a242407_list !! (n-1)
a242407_list = filter ((== 0) . a242400) [0..]

Crossrefs

Cf. A242408 (complement), A003714, A039691, A007089.

Sequence in context: A334860 A082976 A343382 * A047419 A135205 A145733

Adjacent sequences: A242404 A242405 A242406 * A242408 A242409 A242410

Keyword

nonn,base

Author

Reinhard Zumkeller, May 13 2014

Status

approved