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

Author

Reinhard Zumkeller, May 13 2014

Keywords

• nonn
• base

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.

Examples

			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 ..
		

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
• Eric Weisstein's World of Mathematics, Ternary.
• Wikipedia, Ternary numeral system

Crossrefs

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

Programs

Haskell

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

Mathematica

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