A242408 Numbers such that in ternary representation at least one pair of adjacent digits has a sum greater than 2.

5, 7, 8, 14, 15, 16, 17, 21, 22, 23, 24, 25, 26, 32, 34, 35, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 59, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 86, 88, 89, 95, 96, 97, 98, 102, 103, 104, 105, 106, 107, 113

Offset

1,1

Comments

A242400(a(n)) > 0;

A242399(a(n)) < 4*a(n).

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:
.  5  7  8  14  15  16  17  21  22  23  24  25  26   32   34   35   41 ..
. 12 21 22 112 120 121 122 210 211 212 220 221 222 1012 1021 1022 1112 ..

Mathematica

Select[Range[200], Max[Total/@Partition[IntegerDigits[#, 3], 2, 1]]>2&] (* Harvey P. Dale, Feb 12 2016 *)

Prog

(Haskell)
a242408 n = a242408_list !! (n-1)
a242408_list = filter ((> 0) . a242400) [0..]

Crossrefs

Cf. A242407 (complement), A004780.

Sequence in context: A047477 A216555 A288151 * A171952 A238011 A140237

Adjacent sequences: A242405 A242406 A242407 * A242409 A242410 A242411

Keyword

nonn,base

Author

Reinhard Zumkeller, May 13 2014

Status

approved