A320273 Arrange ternary integers in lexicographic order. a(n) is the index of the n-th largest number in this sequence as interpreted in base 3/2 (starting from 0).

0, 1, 3, 2, 9, 4, 6, 10, 27, 5, 12, 7, 11, 28, 18, 13, 30, 8, 81, 15, 29, 19, 36, 14, 31, 21, 82, 16, 33, 20, 84, 37, 54, 32, 22, 83, 39, 17, 90, 34, 24, 85, 243, 38, 55, 45, 23, 87, 40, 57, 91, 35, 108, 25, 86, 244, 42, 56, 93, 46, 63, 88, 246, 41, 58, 92, 48, 109, 26, 99, 245, 43, 60, 94, 252, 47, 111, 64, 89

Offset

0,3

Comments

Every nonnegative integer appears exactly once.

The inverse is sequence A320274.

Links

Table of n, a(n) for n=0..78.

Example

The ternary integers are: 0, 1, 2, 10, 11, 12, 20, 21, 22, 100 and so on. The values of these numbers interpreted in base 3/2 are 0, 1, 2, 1.5, 2.5, 3.5, 3, 4, 5, 2.25  and so on. The values in ascending order are: 0, 1, 1.5, 2, 2.25 and so on. They correspond to indices 0, 1, 3, 2, 9, and so on, which is our sequence.

Crossrefs

Cf. A320274, A024629.

Sequence in context: A325984 A178774 A379658 * A379260 A266636 A182652

Adjacent sequences: A320270 A320271 A320272 * A320274 A320275 A320276

Keyword

nonn,base

Author

Tanya Khovanova and PRIMES STEP Junior group, Oct 08 2018

Status

approved